Created Category model, Category controller, and associated views

* Category model included validation for presence: true
* Category controller included index and create actions
* Created category views for index and _category partial
* Index view includes form to create new category
* Initially created new view for category but deleted bc not needed
* Created location show view to display category partial
* Modified routes to include routes for category index and create
* Deleted multiple ~HEAD files created when resolving github issues
* Deleted bin/rake, bin/rails, log/development bc of above
* Deleted extra lines in views and category model
* Modified Gemfile to delete gem spring reference and comments on other gems