Overriding default id in mongoid

This is an easy one, just want to make sure it's clear.

Add the following field to your model:

field :_id, type: Moped::BSON::ObjectId

And to allow setting it:

1 def id=(id)
2   self[:_id] = id
3 end

Now you can just do obj.id=[Some ObjectId] and save the object.