diff --git a/app/helpers/file_helper.rb b/app/helpers/file_helper.rb
index c4d904ef4..8267a611a 100644
--- a/app/helpers/file_helper.rb
+++ b/app/helpers/file_helper.rb
@@ -425,7 +425,7 @@ def write_entries_to_zip(entries, disk_root_path, zip_root_path, path, zip)
         # puts "subdir: #{subdir}"
         write_entries_to_zip(subdir, disk_root_path, zip_root_path, file_path, zip)
       else
-        # puts "Adding file: #{disk_file_path} -- #{File.exists? disk_file_path}"
+        # puts "Adding file: #{disk_file_path} -- #{File.exist? disk_file_path}"
         zip.get_output_stream(zip_file_path) do |f|
           f.puts(File.open(disk_file_path, 'rb').read)
         end
diff --git a/app/models/overseer_assessment.rb b/app/models/overseer_assessment.rb
index eb67beb30..3219ee033 100644
--- a/app/models/overseer_assessment.rb
+++ b/app/models/overseer_assessment.rb
@@ -51,7 +51,7 @@ def self.create_for(task)
   end
 
   def has_submission_files?
-    File.exists? submission_zip_file_name
+    File.exist? submission_zip_file_name
   end
 
   def submission_zip_file_name
@@ -155,7 +155,7 @@ def send_to_overseer()
       return nil
     end
 
-    unless File.exists? submission_zip_file_name
+    unless File.exist? submission_zip_file_name
       puts "ERROR: Student submission history zip file doesn't exist #{submission_zip_file_name}. Unable to send - OverseerAssessment #{id}"
       return nil
     end
@@ -166,7 +166,7 @@ def send_to_overseer()
       return nil
     end
 
-    unless File.exists? assessment_resources_path
+    unless File.exist? assessment_resources_path
       puts "ERROR: Unable to fine assessment resources - OverseerAssessment #{id}"
       return nil
     end
diff --git a/app/models/task.rb b/app/models/task.rb
index 38cf9d805..42a466feb 100644
--- a/app/models/task.rb
+++ b/app/models/task.rb
@@ -799,7 +799,7 @@ def has_new_files?
   end
 
   def has_done_file?
-    File.exists? zip_file_path_for_done_task
+    File.exist? zip_file_path_for_done_task
   end
 
   #
@@ -1017,7 +1017,7 @@ def portfolio_evidence_path
   def portfolio_evidence_path=(value)
     # Strip the student work directory to store in database as relative path
     self.portfolio_evidence = value.present? ? value.sub(FileHelper.student_work_dir,'') : nil
-  end  
+  end
 
   def final_pdf_path
     if group_task?
@@ -1248,7 +1248,7 @@ def accept_submission(current_user, files, _student, ui, contributions, trigger,
     enqueued_dir = File.join(FileHelper.student_work_dir(:new, nil, true), id.to_s)
 
     # Move files into place, deleting existing files if present.
-    if not File.exists? enqueued_dir
+    if not File.exist? enqueued_dir
       logger.debug "Creating student work new dir #{enqueued_dir}"
       FileUtils.mkdir_p enqueued_dir
     end
@@ -1259,7 +1259,7 @@ def accept_submission(current_user, files, _student, ui, contributions, trigger,
 
     # Delete the tmp dir
     logger.debug "Deleting student work dir: #{tmp_dir}"
-    FileUtils.rm_rf tmp_dir if File.exists? tmp_dir
+    FileUtils.rm_rf tmp_dir if File.exist? tmp_dir
 
     logger.info "Submission accepted! Status for task #{id} is now #{trigger}"
   end
@@ -1270,10 +1270,10 @@ def delete_associated_files
         group_submission.destroy
       else
         zip_file = zip_file_path_for_done_task()
-        if zip_file && File.exists?(zip_file)
+        if zip_file && File.exist?(zip_file)
           FileUtils.rm zip_file
         end
-        if portfolio_evidence_path.present? && File.exists?(portfolio_evidence_path)
+        if portfolio_evidence_path.present? && File.exist?(portfolio_evidence_path)
           FileUtils.rm portfolio_evidence_path
         end
 
diff --git a/app/models/task_definition.rb b/app/models/task_definition.rb
index 08a1c1218..cb5e5584e 100644
--- a/app/models/task_definition.rb
+++ b/app/models/task_definition.rb
@@ -116,15 +116,15 @@ def remove_old_group_submissions
 
   def move_files_on_abbreviation_change
     old_abbr = saved_change_to_abbreviation[0] # 0 is original abbreviation
-    if File.exists? task_sheet_with_abbreviation(old_abbr)
+    if File.exist? task_sheet_with_abbreviation(old_abbr)
       FileUtils.mv(task_sheet_with_abbreviation(old_abbr), task_sheet())
     end
 
-    if File.exists? task_resources_with_abbreviation(old_abbr)
+    if File.exist? task_resources_with_abbreviation(old_abbr)
       FileUtils.mv(task_resources_with_abbreviation(old_abbr), task_resources())
     end
 
-    if File.exists? task_assessment_resources_with_abbreviation(old_abbr)
+    if File.exist? task_assessment_resources_with_abbreviation(old_abbr)
       FileUtils.mv(task_assessment_resources_with_abbreviation(old_abbr), task_assessment_resources())
     end
   end
@@ -340,8 +340,8 @@ def clear_related_plagiarism
     end
   end
 
-  def self.to_csv(task_definitions, options = {})
-    CSV.generate(options) do |csv|
+  def self.to_csv(task_definitions)
+    CSV.generate() do |csv|
       csv << csv_columns
       task_definitions.each do |task_definition|
         csv << task_definition.to_csv_row
diff --git a/app/models/unit.rb b/app/models/unit.rb
index 4e742d435..d0de91794 100644
--- a/app/models/unit.rb
+++ b/app/models/unit.rb
@@ -717,7 +717,7 @@ def update_student_enrolments(changes, import_settings, result)
         last_name = last_name || first_name
         nickname = nickname || first_name
 
-        if !email =~ /\A([^@\s]+)@((?:[-a-z0-9]+\.)+[a-z]{2,})\z/i
+        if email !~ /\A([^@\s]+)@((?:[-a-z0-9]+\.)+[a-z]{2,})\z/i
           errors << { row: row, message: "Invalid email address (#{email})" }
           next
         end
@@ -1338,12 +1338,12 @@ def tutorial_stream_abbr
     tutorial_streams.map{|ts| ts.abbreviation }
   end
 
-  def task_completion_csv(options = {})
+  def task_completion_csv
     task_def_by_grade = task_definitions_by_grade
     streams = tutorial_streams
     grp_sets = group_sets
 
-    CSV.generate(options) do |csv|
+    CSV.generate() do |csv|
       # Add header row
       csv << [
         'Student ID',
@@ -1407,7 +1407,7 @@ def task_completion_csv(options = {})
             "#{row['first_name']} #{row['last_name']}",
             GradeHelper.grade_for(row['target_grade']),
             row['email'],
-            row['portfolio_production_date'].present? && !row['compile_portfolio'] && File.exists?(FileHelper.student_portfolio_path(self, row['username'], true)),
+            row['portfolio_production_date'].present? && !row['compile_portfolio'] && File.exist?(FileHelper.student_portfolio_path(self, row['username'], true)),
             row['grade'] > 0 ? row['grade'] : nil,
             row['grade_rationale']
           ] + [1].map do
@@ -1437,7 +1437,7 @@ def get_portfolio_zip(current_user)
     filename = FileHelper.sanitized_filename("portfolios-#{code}-#{current_user.username}")
     result = "#{FileHelper.tmp_file(filename)}.zip"
 
-    return result if File.exists?(result)
+    return result if File.exist?(result)
     # Create a new zip
     Zip::File.open(result, Zip::File::CREATE) do |zip|
       active_projects.each do |project|
@@ -1462,7 +1462,7 @@ def get_task_resources_zip
     # Get a temp file path
     result = FileHelper.tmp_file("task-resources-#{code}.zip")
 
-    return result if File.exists?(result)
+    return result if File.exist?(result)
 
     # Create a new zip
     Zip::File.open(result, Zip::File::CREATE) do |zip|
@@ -1490,7 +1490,7 @@ def get_task_submissions_pdf_zip(current_user, td)
 
     tasks_with_files = td.related_tasks_with_files
 
-    return result if File.exists?(result)
+    return result if File.exist?(result)
 
     # Create a new zip
     Zip::File.open(result, Zip::File::CREATE) do |zip|
@@ -1523,7 +1523,7 @@ def get_task_submissions_zip(current_user, td)
 
     tasks_with_files = td.related_tasks_with_files
 
-    return result if File.exists?(result)
+    return result if File.exist?(result)
 
     # Create a new zip
     Zip::File.open(result, Zip::File::CREATE) do |zip|
@@ -2275,8 +2275,8 @@ def student_grades_csv
   end
 
   # Used to calculate the number of assessment each tutor has performed
-  def tutor_assessment_csv(options = {})
-    CSV.generate(options) do |csv|
+  def tutor_assessment_csv
+    CSV.generate() do |csv|
       csv << [
         'Username',
         'Tutor Name',
@@ -2322,7 +2322,7 @@ def generate_batch_task_zip(user, tasks)
 
     output_zip = FileHelper.tmp_file("batch_ready_for_feedback_#{code}_#{user.username}.zip")
 
-    return result if File.exists?(output_zip)
+    return result if File.exist?(output_zip)
 
     # Create a new zip
     Zip::File.open(output_zip, Zip::File::CREATE) do |zip|
diff --git a/config/secrets.yml b/config/secrets.yml
index e59d46c66..71241f314 100644
--- a/config/secrets.yml
+++ b/config/secrets.yml
@@ -1,13 +1,21 @@
-development: &development
+development: &development-settings
   secret_key_base:   <%= ENV['DF_SECRET_KEY_BASE']   || '9e010ee2f52af762916406fd2ac488c5694a6cc784777136e657511f8bbc7a73f96d59c0a9a778a0d7cf6406f8ecbf77efe4701dfbd63d8248fc7cc7f32dea97' %>
   secret_key_attr:   <%= ENV['DF_SECRET_KEY_ATTR']   || 'e69fc5960ca0e8700844a3a25fe80373b41c0a265d342eba06950113f3766fd983bad9ec51bf36eb615d9711bfe1dd90b8e35f01841b323f604ffee857e32055' %>
   secret_key_devise: <%= ENV['DF_SECRET_KEY_DEVISE'] || 'f4e23c4388dc600e503a09ad057b8271d8fcf4c2cd6723b44f33db638e49075fe96bc545eed9110ded0c5df505625d4e1c838b718349eecf1d39270d0829d5b9' %>
   secret_key_aaf:    <%= ENV['DF_SECRET_KEY_AAF']    || 'secretsecret12345' %>
   secret_key_moss:   <%= ENV['DF_SECRET_KEY_MOSS'] %>
 test:
-  <<: *development
+  secret_key_base:   <%= ENV['DF_SECRET_KEY_BASE']   || '9e010ee2f52af762916406fd2ac488c5694a6cc784777136e657511f8bbc7a73f96d59c0a9a778a0d7cf6406f8ecbf77efe4701dfbd63d8248fc7cc7f32dea97' %>
+  secret_key_attr:   <%= ENV['DF_SECRET_KEY_ATTR']   || 'e69fc5960ca0e8700844a3a25fe80373b41c0a265d342eba06950113f3766fd983bad9ec51bf36eb615d9711bfe1dd90b8e35f01841b323f604ffee857e32055' %>
+  secret_key_devise: <%= ENV['DF_SECRET_KEY_DEVISE'] || 'f4e23c4388dc600e503a09ad057b8271d8fcf4c2cd6723b44f33db638e49075fe96bc545eed9110ded0c5df505625d4e1c838b718349eecf1d39270d0829d5b9' %>
+  secret_key_aaf:    <%= ENV['DF_SECRET_KEY_AAF']    || 'secretsecret12345' %>
+  secret_key_moss:   <%= ENV['DF_SECRET_KEY_MOSS'] %>
 staging:
-  <<: *development
+  secret_key_base:   <%= ENV['DF_SECRET_KEY_BASE']   || '9e010ee2f52af762916406fd2ac488c5694a6cc784777136e657511f8bbc7a73f96d59c0a9a778a0d7cf6406f8ecbf77efe4701dfbd63d8248fc7cc7f32dea97' %>
+  secret_key_attr:   <%= ENV['DF_SECRET_KEY_ATTR']   || 'e69fc5960ca0e8700844a3a25fe80373b41c0a265d342eba06950113f3766fd983bad9ec51bf36eb615d9711bfe1dd90b8e35f01841b323f604ffee857e32055' %>
+  secret_key_devise: <%= ENV['DF_SECRET_KEY_DEVISE'] || 'f4e23c4388dc600e503a09ad057b8271d8fcf4c2cd6723b44f33db638e49075fe96bc545eed9110ded0c5df505625d4e1c838b718349eecf1d39270d0829d5b9' %>
+  secret_key_aaf:    <%= ENV['DF_SECRET_KEY_AAF']    || 'secretsecret12345' %>
+  secret_key_moss:   <%= ENV['DF_SECRET_KEY_MOSS'] %>
 production:
   secret_key_base:   <%= ENV['DF_SECRET_KEY_BASE']   %>
   secret_key_attr:   <%= ENV['DF_SECRET_KEY_ATTR']   %>
diff --git a/lib/helpers/database_populator.rb b/lib/helpers/database_populator.rb
index 304630e4e..a7aa80b64 100644
--- a/lib/helpers/database_populator.rb
+++ b/lib/helpers/database_populator.rb
@@ -473,7 +473,7 @@ def self.assess_task(proj, task, tutor, status, complete_date)
     end
 
     pdf_path = task.final_pdf_path
-    if pdf_path && !File.exists?(pdf_path)
+    if pdf_path && !File.exist?(pdf_path)
       FileUtils.ln_s(Rails.root.join('test_files', 'unit_files', 'sample-student-submission.pdf'), pdf_path)
     end
 
@@ -486,7 +486,7 @@ def self.generate_portfolio(project)
     FileUtils.mkdir_p(portfolio_tmp_dir)
 
     lsr_path = File.join(portfolio_tmp_dir, "000-document-LearningSummaryReport.pdf")
-    FileUtils.ln_s(Rails.root.join('test_files', 'unit_files', 'sample-learning-summary.pdf'), lsr_path) unless File.exists? lsr_path
+    FileUtils.ln_s(Rails.root.join('test_files', 'unit_files', 'sample-learning-summary.pdf'), lsr_path) unless File.exist? lsr_path
     project.compile_portfolio = true
     project.create_portfolio
   end
@@ -508,7 +508,7 @@ def echo_line *args
   def generate_tasks_for_unit(unit, unit_details)
     echo "----> Generating #{unit_details[:num_tasks]} tasks"
 
-    if File.exists? Rails.root.join('test_files',"#{unit.code}-Tasks.csv")
+    if File.exist? Rails.root.join('test_files',"#{unit.code}-Tasks.csv")
       unit.import_tasks_from_csv File.open(Rails.root.join('test_files',"#{unit.code}-Tasks.csv"))
       unit.import_task_files_from_zip Rails.root.join('test_files',"#{unit.code}-Tasks.zip")
       return
@@ -546,7 +546,7 @@ def generate_and_align_ilos_for_unit(unit, unit_details)
     # Create the ILOs
     echo "----> Adding #{unit_details[:ilos]} ILOs"
 
-    if File.exists? Rails.root.join('test_files',"#{unit.code}-Outcomes.csv")
+    if File.exist? Rails.root.join('test_files',"#{unit.code}-Outcomes.csv")
       unit.import_outcomes_from_csv File.open(Rails.root.join('test_files',"#{unit.code}-Outcomes.csv"))
       unit.import_task_alignment_from_csv File.open(Rails.root.join('test_files',"#{unit.code}-Alignment.csv")), nil
       return