I\'m relatively new to rails and finally found the right way to use accepts_nested_attributes_for.
accepts_nested_attributes_for
However, there are some serious resources on the web who
Railscasts also has an episode on nested form models: http://railscasts.com/episodes/196-nested-model-form-revised?view=asciicast
As shown in the comments, cocoon gem simplifies a lot: https://github.com/nathanvda/cocoon