cleaning up specs
Removing unnecessary "to_s"

`#{...}` calls `to_s` automatically under the hood - no need to explicitly include it.
refactoring install generator
interpolating strings instead of using to_s and to_sym
make tests compatible with Rails 4
cleaning up specs
refactoring WebhooksController and its specs
Merge branch 'generators'
Merge branch 'webhooks-controller'
Merge branch 'specs'
Merge branch 'spec-cleanup'