Added hashtag functionality, list by hashtag.
Update schema.rb file.
Ping to Dan.
fix index display for hashtags and bookmarks
Refactor.
WIP
Add tests and refactoring.
Merge pull request #19 from coloradobum/add_hashtags

clickable_hashtags
Users can unfavorite bookmarks
  Added delete action to favorites_controller.rb
  If user is logged in, users can unfavorite a bookmark
  If no user, added Sign up and Login links to bookmark show view
modify favorites feature spec