Allow model option for associations to be passed as string or constant.

[asedge]

Passing model as a string is preferred so that the order of dependent class definitions doesn't matter.

Defining the model as a constant like this will fail with a NameError:

class Foo
  belongs_to :bar, model: Bar
end
class Bar; end

This could be problematic in Rails with the load order being unknown. By defining the model as a string we can lazy evaluate the constant which should be safer:

class Foo
  belongs_to :bar, model: 'Bar'
end
class Bar; end

[JeffLuckett]

I like it.

[TABeauchat]

No comments. All looks good.

[TABeauchat]

On a side note...we will probably want to alert everyone that we will need to update all our current AF models for this.

[asedge]

On a side note...we will probably want to alert everyone that we will need to update all our current AF models for this.

It's probably not a bad idea to throw the information in one of our larger slack channels (I can do that) to make everyone aware. It's a backwards compatible change so no immediate action is needed.