Update to latest easy_auth

Beside the test files changes, I took the freedom to cleanup the way tests are set up.

I removed helpers file since the code there was not used anywhere.
I replaced the old hackish way of database setup by introducing `rails-dummy` gem which uses a rails template to achieve a proper setup.
I removed ruby-debugger. This was not used anywhere and was not installing for me.
I also updated gems, and removed some of the setup code that is not relevant anymore.

Along with this, I updated the Angel List plugin I use.

By running `bundle exec rake` it should generate the dummy app and tests should pass.
You can set `SKIP_DUMMY_APP=1` in order to skip dummy app generation every time.

Please review.
Thanks.