Why is my user_id nil? - ruby-on-rails

Question

def destroy
#dignity.destroy
end
Sorry, that's not code, that's just how I feel right now. I know there are a ton of beginner questions on Devise, I think I looked at almost every single one.
I have a very simple Devise setup in Rails 3. I did:
rails generate devise User
I'm also running the rails 3 GeoKit plugin,(not sure if that's relevant, just know that I have this other model) so I have another model called Location, and it acts_as_mappable.
Before I post the code, the basic problem is that I cannot seem to get user_id to auto-increment. It was my understanding that a bit of Rails magic should take care of this for me, if I add a column called user_id to Location class. (which I did through a migration.) and then simply set has_many and belongs_to accordingly. (see below)
I can't figure out why user_id is always nil. Does it have something to do with the way the Devise engine works? I am pretty sure I've made this type of association work in the past in the same way when I wasn't using Devise.
user.rb:
class User < ActiveRecord::Base
has_many :locations
# Include default devise modules. Others available are:
# :token_authenticatable, :confirmable, :lockable and :timeoutable
devise :database_authenticatable, :registerable,
:recoverable, :rememberable, :trackable, :validatable
# Setup accessible (or protected) attributes for your model
attr_accessible :email, :password, :password_confirmation, :remember_me
end
location.rb:
class Location < ActiveRecord::Base
belongs_to :user
attr_accessible :street_adress, :city, :state, :zip, :item, :user_id
acts_as_mappable :auto_geocode => true
def address
return "#{self.street_adress}, #{self.city}, #{self.state}, #{self.zip}, #{self.item}"
end
end
here is the migration that added the column:
class AddUseridToLocation < ActiveRecord::Migration
def self.up
add_column :locations, :user_id, :integer
end
def self.down
remove_column :locations, :user_id
end
end
And finally, here is the schema.rb:
ActiveRecord::Schema.define(:version => 20110213035432) do
create_table "locations", :force => true do |t|
t.string "street_adress"
t.string "city"
t.string "state"
t.string "zip"
t.float "lat"
t.float "lng"
t.datetime "created_at"
t.datetime "updated_at"
t.string "item"
t.integer "user_id"
end
create_table "users", :force => true do |t|
t.string "email", :default => "", :null => false
t.string "encrypted_password", :limit => 128, :default => "", :null => false
t.string "password_salt", :default => "", :null => false
t.string "reset_password_token"
t.string "remember_token"
t.datetime "remember_created_at"
t.integer "sign_in_count", :default => 0
t.datetime "current_sign_in_at"
t.datetime "last_sign_in_at"
t.string "current_sign_in_ip"
t.string "last_sign_in_ip"
t.datetime "created_at"
t.datetime "updated_at"
end
add_index "users", ["email"], :name => "index_users_on_email", :unique => true
add_index "users", ["reset_password_token"], :name => "index_users_on_reset_password_token", :unique => true
end
EDIT: I'm okay with a RTFM response, as long as I can get a little push in the right direction. I have a suspicion that I need to tell rails something in the create action of my locations_controller.rb ? Someone just give me a little hint here!

Answer 1

def destroy
#dignity.destroy
end
Clearly the first thing to be done is:
raise self.esteem
You say you can't get user_id to "autoincrement". I think what you meant is that user_id is not being assigned (i.e. it is always nil). Can you show the part of the code that assigns a location to a user? Either of these should work:
#user.locations.build
#user.locations << Location.new
EDIT
To expand on this a bit, say you have a request that looks like this:
POST /users/37/locations
And the submitted form contains input name=user[location][name] value="Paris". A typical Rails controller create action might look like this:
def create
#user = User.find(params[:user_id])
#user.locations.build(params[:user][:location])
if #user.save
flash[:notice] = "Location created successfully"
redirect_to user_locations_path(#user)
else
render :new
end
end
The 'magic' is basically Rails inferring from the has_many statement that it needs to set the value of the foreign key column ('user_id') in the related row in the locations table. When you call #user.save it adds a new row in locations and sets user_id to the value of #user.id.