Associate Post and User with Comment

app/models/comment.rb

@@ -0,0 +1,4 @@
+class Comment < ApplicationRecord
+  belongs_to :post
+  belongs_to :commented_by, class_name: 'User'
+end

app/models/post.rb

@@ -1,5 +1,6 @@
 class Post < ApplicationRecord
   belongs_to :created_by, class_name: 'User'
+  has_many :comments, dependent: :destroy
 
   validates :title, presence: true
 

app/models/user.rb

@@ -2,6 +2,7 @@ class User < ActiveRecord::Base
   include Authenticator
 
   has_many :posts, foreign_key: 'created_by_id'
+  has_many :comments, foreign_key: 'commented_by_id'
 
   class << self
     def find_or_create_from(auth)