Migration example

gistfile1.rb

# Migration (created from Devise)
class DeviseCreateUsers < ActiveRecord::Migration
  def self.up
    create_table(:users) do |t|
      t.database_authenticatable :null => false
      t.recoverable
      t.rememberable
      t.trackable
      
      t.string :name

      # t.confirmable
      # t.lockable :lock_strategy => :failed_attempts, :unlock_strategy => :both
      # t.token_authenticatable


      t.timestamps
    end

    add_index :users, :email,                :unique => true
    add_index :users, :reset_password_token, :unique => true
    # add_index :users, :confirmation_token,   :unique => true
    # add_index :users, :unlock_token,         :unique => true
  end

  def self.down
    drop_table :users
  end
end

# db/schema.rb
create_table "users", :id => false, :force => true do |t|
    t.integer  "id",                                                  :null => false
    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.string   "name"
    t.datetime "created_at"
    t.datetime "updated_at"
  end

# Migration command
rake db:migrate && rake db:test:prepare

# Error received when creating a record
ActiveRecord::StatementInvalid: PG::Error: ERROR:  null value in column "id" violates not-null constraint
: INSERT INTO "users" ("created_at", "current_sign_in_at", "current_sign_in_ip", "email", "encrypted_password", "id", "last_sign_in_at", "last_sign_in_ip", "name", "password_salt", "remember_created_at", "remember_token", "reset_password_token", "sign_in_count", "updated_at") VALUES ($1, $2, $3, $4, $5, $6, $7, $8, $9, $10, $11, $12, $13, $14, $15)

# This happens when running a test
# or when in console with RAILS_ENV=test