fix bugs

.gitignore

@@ -6,7 +6,6 @@
 # Gradle build files
 /.gradle/
 /build/
-src/main/resources/docs/
 
 # MacOS custom attributes files created by Finder
 .DS_Store

src/main/java/seedu/duke/TipsException.java

@@ -0,0 +1,26 @@
+package seedu.duke;
+
+/**
+ * Any excption will be throw in this type, which contains information about
+ * this exception and the possible solution.
+ * It's suggested to use toString() to show the content of this exception so
+ * that the tester can have a clear view of the error reason and the possible
+ * solution to solve this error.
+ */
+public class TipsException extends Exception {
+    public String error, tips;
+
+    /**
+     * Creating a new Tips Exception.
+     */
+    public TipsException(String error, String tips) {
+        this.error = error;
+        this.tips = tips;
+    }
+
+    @Override
+    public String toString() {
+        return "Error: " + error
+                + "\nTips: " + tips;
+    }
+}

src/main/java/seedu/duke/commands/meal/AddCommand.java

@@ -1,7 +1,7 @@
 package seedu.duke.commands.meal;
 
 import seedu.duke.commands.CommandResult;
-import seedu.duke.data.meal.Meal;
+import seedu.duke.meal.*;
 import seedu.duke.data.Date;
 
 import java.util.List;

src/main/java/seedu/duke/commands/meal/DeleteCommand.java

@@ -1,6 +1,7 @@
 package seedu.duke.commands.meal;
 
 import seedu.duke.commands.CommandResult;
+import seedu.duke.meal.*;
 
 import java.util.List;
 

src/main/java/seedu/duke/commands/meal/ListCommand.java

@@ -1,9 +1,7 @@
 package seedu.duke.commands.meal;
 
 import seedu.duke.commands.CommandResult;
-import seedu.duke.data.meal.Category;
-import seedu.duke.data.meal.CategoryParser;
-import seedu.duke.data.meal.Meal;
+import seedu.duke.meal.*;
 
 import java.util.ArrayList;
 import java.util.List;

src/main/java/seedu/duke/commands/meal/MealCommand.java

@@ -5,7 +5,7 @@
 
 import seedu.duke.commands.Command;
 import seedu.duke.commands.CommandResult;
-import seedu.duke.data.meal.Meal;
+import seedu.duke.meal.*;
 
 public class MealCommand extends Command {
     protected static ArrayList<Meal> meals;

src/main/java/seedu/duke/meal/Category.java

@@ -0,0 +1,5 @@
+package seedu.duke.meal;
+
+public enum Category {
+    staple_food, snack, beverage
+}

src/main/java/seedu/duke/meal/CategoryParser.java

@@ -0,0 +1,19 @@
+package seedu.duke.meal;
+
+public class CategoryParser {
+    private static Category[] categories = Category.values();
+
+    public static Category Parse(String categoryString) throws Exception {
+        try {
+            int index = Integer.parseInt(categoryString);
+            return categories[index];
+        } catch (Exception exception1) {
+            try {
+                return Category.valueOf(categoryString);
+            } catch (Exception exception2) {
+                throw new Exception(
+                        "Unable to parse Category String into Category enum.\nPlease input a number ranging in 0~2 or a valid category type.");
+            }
+        }
+    }
+}

src/main/java/seedu/duke/meal/Meal.java

@@ -0,0 +1,22 @@
+package seedu.duke.meal;
+
+import seedu.duke.data.Date;
+
+public class Meal {
+    public String name;
+    public int calories;
+    public Date time;
+    public Category category;
+
+    public Meal(String name, int calories, String category, Date time) throws Exception {
+        this.name = name;
+        this.calories = calories;
+        this.time = time;
+        this.category = CategoryParser.Parse(category);
+    }
+
+    @Override
+    public String toString() {
+        return name + "(" + calories + " calories, " + category + ", on " + time.toString() + ")";
+    }
+}