Primary key type in migration template

[filip373]

Adds primary key type to migration creating template in Rails 5. It uses the configuration set in Rails generator as below:

config.generators do |g|
  g.orm :active_record, primary_key_type: :uuid
end

Resolves #4413

[tegon]

Hello, @filip373, thanks for your contribution.
Your code looks good to me, could you please do a rebase with master to see if the build passes?

[filip373]

Hi @tegon, thanks for your response.
I've rebased the code and applied a small patch so the build passes.

[tegon]

Thanks, @filip373!