Installation fails in Rails 5 due to new migration rules - easy fix

[katiekeel]

Hi, thanks for the awesome gem! I just installed it on an existing Rails 5 app and, following the instructions in the README, the installation fails when attempting to run the new migrations:

I was able to easily fix them and run the migrations simply by appending my Rails version in brackets to the end of the migration class name, as pictured here:

I then continued the migration with rails db:migrate, which ran successfully, and continued adding the code that the tutorial indicated should be there at the end of setup but wasn't.

Happy to work on a pull request if this gem is still actively worked on and this might be a solution.

[AlexanderZaytsev]

@katiekeel a pull request will be much appreciated! We could use Rails::VERSION::MAJOR to detect if it's Rails 5, and if it yes, we append the exact release to the migration templates.