Make sure that `feature:install` generators are broken both on Rails 3 and 4
fixes #10 NotImplementedError for `next_migration_number` on both Rails 3 and 4
fixes #11 The generator is not compatible with Rails 4: NoMethodError for `attr_accessible` on Rails 4 w/o protected_attributes gem
Merge pull request #12 from mumoshu/add-tests-and-fix-errors-for-generator

Add tests and fix errors for generator