Fix ActiveRecord::DuplicateMigrationVersionError error

[artofhuman]

ActiveRecord::DuplicateMigrationVersionError occurs when engine initializer add migrations like this:

class Engine < ::Rails::Engine
  initializer :same_initializer do |app|
    app.config.paths['db/migrate'].concat(config.paths['db/migrate'].expanded)
  end
end

[bibendi]

@pat :up:

[bibendi]

@pat Do you maintain this repo?

[pat]

I do, and I'm well aware I'm much behind with some pull requests…

My concern is that Combustion is ideally built to work with Rails 3.2 onwards, but there are no tests. Writing tests for a testing library and getting them to work across Rails versions is painful - but currently I wonder whether each pull request is catering to behaviour in specific Rails versions, and I just don't know. I've not made the time to write a testing harness or something that would make me more certain, but that's the path I'd like to get things along eventually.

I guess a starting point is: what versions of Rails has this pull request been tested against? :)

[artofhuman]

@pat we tested rails 3.1 3.2 and 4.0 I think i can create 2 gems to reproduce this problem

[artofhuman]

@pat, i add test case, look plz

[pat]

Fantastic, thanks! Just merged it in :D

[artofhuman]

@pat thanks