HABTM relations insertion

First off, you need to use the has_and_belongs_to_many relationship.

#user.rb
has_and_belongs_to_many :notes

Surprisingly, you won't need anything defined in #notes.rb - all
handled from the above declaration.

Then in your controller:

@user.notes = Note.new(params[:notes])

A good example can be found here:

http://jrhicks.net/Projects/rails/has_many_and_belongs_to_many.pdf

HTH

Ross