Fix tests on rails 4.2

From http://edgeguides.rubyonrails.org/4_2_release_notes.html#action-pack

> When calling the process helpers in an integration test the path needs to have a leading slash.
> Previously you could omit it but that was a byproduct of the implementation and
> not an intentional feature.

- Fixed all get requests to have a forward slash to fix failing tests on rails 4.2