upgrade to rails 4

includes some amendments to specs to make them work
remove all frontend

API will be sending only JSON. Remove all frontend-related code & gems
use `foreman` to start webapp and worker
mock gds-sso authentication when running under `docker`env
mock `#authenticate_user!` when running under `docker` env
follow rails autoloading rules

We began getting a `ActiveSupport::Concern::MultipleIncludedBlocks`

- `Model::Declarable` -> `Declarable`
- `Models::Formatter` -> `Formatter`
Update controller_methods.rb
Merge pull request #6 from bitzesty/docker-env

mock gds-sso authentication when running under `docker`env