Removed 'has_multi_record_ancestor' attribute of a question to be sent from backbone to rails.
Added :medium as hash in photo decorator
Fixed the reports page by avoiding questions which don't have complete responses
Updated the query to be much faster
Improved the query
Fixed bug by taking about response state
Changed the questions_for_reports query
Fixed the 'Download Excel' link on the Reports page.
Include categories and options in ResponseControllerAPI#Show
Add ability for a viewer
Add a new ability file for the viewer role.
If not one of the supported roles, generic permissions are in Ability
Archived surveys are not returned in API::SurveysController#index.
Authorize API::QuestionsController through `Survey`.
When authorising QuestionsController methods using the parent survey, use `try` in case it doesn't exist.
Authorize the API::CategoryController actions using the parent survey.
Don't authorise Surveys#questions_count.

It fetches counts only for authorised surveys anyway.
Authorize API::OptionsController using the parent survey.
Option#survey delegates to it's parent question.

Update the version of `shoulda-matchers` so we get the `delegate_method` matcher.
Finish up ViewerAbility.

- Add abilities to see responses/reports.
- Add abilities to see surveys shared with his organisation.