Adds new Category model, controller, views

 - moves sorting by category to category model
 - updates nav bar
 - creates categories controller and index action/view
Updates title, adds method to categories controller
Fixes root_url, removes bechdel sorting

 - removes bechdel sorting from root url
 - removes un-needed each loop (creating array of movies
   based on a certain category), since this functionality
   now located in Category model
Merge pull request #6 from jacindaz/categories-model-branch

Categories model branch