add abilities to student for submissions
rewrite admin ability spec to cover all models
add authorization to attendance statistics
define abilities for students

This includes tests for each ability. A CanCan matchers helper is also included to make test writing more clear. See spec/support/matchers/cancan_matchers.rb for more details.
authorize resources in controllers for students

Now all the routes are properly authorizing students. This does
not take care of authorizing admins. Some specs had to be restructured
to be more logically organized with new specs. This therefore created
new cassettes.
define abilities for admins
authorize resources in controllers for admins
add authorzation to payment_method pages
Merge pull request #48 from epicodus/authorizations

Authorizations