Alters submission migration to include image_url, adds post for creating new submission.
Fixes post for making new subreddit, adds redirect.
Creates erb view form for new subreddits.
Fixes form for new submission to subreddit.
Adds get for subreddits newest submissions, adds comments.
Adds get for subreddit submission comments, still needs erb. Adds post for creating comments to a subreddits submission.