[75214236] User can see details of a subscription

* Adds subscription resource to routes file
* Creates controller for subscriptions
[75214236] User can see details of a subscription

* Adds link to subscription in subscription partial
* Creates show view for subscriptions
[75214236] User can see details of a subscription

* Adds specs for subscription controller
[75214236] User can see details of a subscription

* Fix security issue on subscriptions controller
* Fix subscriptions controller specs
Merge pull request #3 from crowdint/feature/create-subscriptions-show-page

Feature/create subscriptions show page