Jorge Medrano

Dynamoid::Persistence#update! should be running :save callbacks

1

`Dynamoid::Persistence#update!` is only running the `:update` callbacks, and never runs the `:save` callbacks

`Dynamoid::Persistence#save` will never run the `:update` callbacks, this implies that `Dynamoid::Fields#update_attributes` and `Dynamoid::Fields#update_attribute` won't run them too

something like this could resolve #192