Initializer does not execute when models reload on Rails 3.1 development environment

We are currently using Ruby 1.9.3, Rails 3.1 (i know, we're working hard to upgrade all our applications).

We're using a module (let's call it 'OurModule' to add a method (let's call it 'OurAddOnMethod' to a model defined in a gem (let'd call that 'GemModel'). We have that module file living in the 'config/initializers' directory.

That file defines the module, and then calls this to include it in the model:

# Include the extension 
GemModel.send(:include, OurModule)

When developing, things work well mostly, but periodically we will get an error that basically says "Undefined method 'OurAddOnMethod' in 'GemModel'". Restarting the server resolves the issue (for a while).

I'm assuming this is happening because the models are reloaded periodically with changes made in the development environment, and it appears that the initializers do not also get reloaded at that time..? It seems like this may not be the best way to set things up; it is quite frustrating to deal with.

Can anyone enlighten me on a better way to achieve this?