generate model for Category and CategoryDare join table
has_many, through model associations made. Calling Dare.first.categories and Category.first.dares works correctly
Category checkbox list added to Dare#new view form using f.association. Updated strong params
Merge pull request #36 from Micahcodes/iss-26-create_category_model_and_associations

Iss 26 create category model and associations

This looks good. Merging now so I can work on seeds file. Micah will continue to write tests and issue another merge request.