Rails 4.0 on Heroku, NoMethodError (undefined method `password_digest=' for #<User

I've seen lots of posts about this error, but I'm still stumped. Edit: https://anthonyroberts.herokuapp.com/signup Michael Hartl's Tutorial, end of Chapter 7, you have a working signup form. Works locally, but returns 500 on Heroku. I've reset the db and run db:migrate on Heroku, to no avail. I tried the Heroku console, and successfully created a User with ``` foo = User.create(name: "Anthony", email: "email@email.com", password: "foobar", password_confirmation: "foobar") ``` This works, and I've got a user. So why does the signup form submission give me this error: ``` NoMethodError (undefined method `password_digest=' for #<User:0x007f02972b7118>): app/controllers/users_controller.rb:12:in `create' ``` here's the user.rb: ``` class User < ActiveRecord::Base before_save { email.downcase! } validates :name, presence: true, length: { maximum: 50 } VALID_EMAIL_REGEX = /\A[\w+\-.]+@[a-z\d\-]+(?:\.[a-z\d\-]+)*\.[a-z]+\z/i validates :email, presence: true, format: { with: VALID_EMAIL_REGEX }, uniqueness: { case_sensitive: false } has_secure_password validates :password, length: { minimum: 6 } end ``` here's the migration to add the password_digest to the model: ``` class AddPasswordDigestToUsers < ActiveRecord::Migration def change add_column :users, :password_digest, :string end end ``` Here's the users_controller.rb: ``` class UsersController < ApplicationController def show @user = User.find(params[:id]) end def new @user = User.new end def create @user = User.new(user_params) if @user.save flash[:success] = "Welcome to the Sample App!" redirect_to @user else render 'new' end end private def user_params params.require(:user).permit(:name, :email, :password, :password_confirmation) end end ``` Here's the new.html.erb template: ``` <% provide(:title, 'Sign up') %> <h1>Sign up</h1> <div class="row"> <div class="span6 offset3"> <%= form_for(@user) do |f| %> <%= render 'shared/error_messages' %> <%= f.label :name %> <%= f.text_field :name %> <%= f.label :email %> <%= f.text_field :email %> <%= f.label :password %> <%= f.password_field :password %> <%= f.label :password_confirmation, "Confirmation" %> <%= f.password_field :password_confirmation %> <%= f.submit "Create my account", class: "btn btn-large btn-primary" %> <% end %> </div> </div> ``` I'm new to RoR, so I'll bet it's a piddly mistake. Thanks in advance.