This partially addresses #293. Since rubocop generated quite a few todos, the commits addressing them are split up into a few different PRs that cover different files.
This is similar to the work Christian Bruckmayer is doing over on
factory_bot. I read that Hound doesn't support the
`inherited_from` key, so I put all of the todos
from the auto-generated `.rubocop_todo.yml` straight into the
`.rubocop.yml`.
fixup! Add RuboCop configuration
* support latest Ruby 2.1
* support latest Ruby 2.2
* support latest Rails 4.2
* drop testing of Ruby 2.0
* drop testing of Rails 4.0
* fix JRuby support
* Remove gemfiles from version control to match same testing style as
Clearance and Suspenders.
* MiniTest does not need to be manually included as it is automatically
included by Rails by default.
* Add spring for Rails 4.1.
* Disable Spring to get specs to pass on Rails 4.1.
* Add therubyrhino for JRuby.
* Remove old references to Rails 3.
* Fix JRuby test where output is "1 runs", not "1 tests".
* Remove Rails 3.0 reference to "turn".
