Adding the Retweet model and updating Tweet.by_user_ids to include the retweets of each user.
Adding RetweetsController#create action.
Adding RetweetsController#destroy action
Adding links to Retweet and Un-Retweet
retweeting should return us to whatever page the link was clicked on
Merge branch 'master' into retweet
ensuring that only retweets which belong to the current user can be deleted
small refactor to avoid code duplication
Adding / updating documentation
Merge branch 'master' into retweet
changing language to Retwet
Merge 'retwet' into complete