Updated code for functionality and added comments

[KarynMC27]

• Updated code to work with newest version of mongoose/node.js
• Added the ability for users to make comments that record the comment, the date the comment was made, and the user who made the comment
• Added a delete button for comments that will only show up for logged-in users on comments that they wrote
• Added title and username to images in the feed
• Added username to posts
• Changed the likes button so that you can only like each post once. It's also a toggle so if you click it again, you unlike the post.
• Made the dates look a little nicer