It seems inelegant to me to split this into two different modules, one to include, the other to extend.
the key thing (one of them) to understand here is that: class methods are singleton methods
It seems inelegant to me to split this into two different modules, one to include, the other to extend.
the key thing (one of them) to understand here is that: class methods are singleton methods
Another possible solution would be to use a class Common instead of a module. But this is just a workaround.