Merge pull request #2 from adeng21/categories

Categories
made Month MVC and incorporated funcationality into divesites
Merge pull request #3 from adeng21/months

made Month MVC and incorporated funcationality into divesites
Added months and categories associations to admin section
Admin can edit and add divesites with categories and months
fixed delete popup errors by deleting turbolinks
Merge pull request #4 from adeng21/admin

Admin
added uniqueness index to category