Rails authentication - Devise nested models - ruby-on-rails-3

Question

This is probably a really simple question but one I've never quite worked out myself being still fairly new to rails.
I've setup devise on one project locally that works very well, however at the time I couldn't think of a way to set authentication up for my models properly, I didn't want the user to have to edit the user details to edit their respective model details at the same time so I put a hidden form in the models form containing the value for the 'current_user.id' to ensure it always saved to the logged in user - however obviously I've realised that the value of this form could be changed to anything via the source and any data re-assigned to any user.
What is the proper way to easily setup models that belong to users, which can be created/edited/deleted etc. against that user independently without having to save user details alongside in the 'accepts_nested_attributes_for' way I've seen before with things like this?
I guess I'm just looking to dig a bit deeper and understand how to relate these models to a user, but the models work completely independently off themselves and don't require user data from the Users model to be saved.
An example data structure is:
User -> Posts and Posts -> Comments where posts/comments can be added/edited deleted without having to change the original user data, an email/password is just used for authentication purposes.
I appreciate the object structure could quite easily be:
User:[{
Posts:[{
"name":"test",
"description":"test"
{
"name":"test2",
"description":"test2"
}]
}]
}]
But in this specific example I would want Posts to be a separate model with their own comments on each and the only relationship to be that the post in question was created by "Joe Bloggs" or UserID 4.
Thanks in advance guys and apologies for the rambling, just want to make sure I make sense!

Answer 1

Using devise you can simply add a line to the create action in the controller that devise recognises and actually does this relationship for you without having to create nested attributes or forms. It's the '#post.user = current_user' line below that automagically does this! So the models are still technically nested if you will but you don't have to change any of your original forms etc. to get them to nest to users correctly, it just passes the user ID.
i.e.
def create
#post = Post.new(params[:post])
#post.user = current_user
respond_to do |format|
if #post.save
format.html { redirect_to #post, :notice => 'Post was successfully created.' }
format.json { render :json => #post, :status => :created, :location => #post }
else
format.html { render :action => "new" }
format.json { render :json => #snippet.errors, :status => :unprocessable_entity }
end
end
end