uninitialized constant DeviseCreateUsers
/app/vendor/bundle/ruby/2.0.0/gems/activesupport-3.2.11/lib/active_support/inflector/methods.rb:230:in `block in constantize'
/app/vendor/bundle/ruby/2.0.0/gems/activesupport-3.2.11/lib/active_support/inflector/methods.rb:229:in `each'
/app/vendor/bundle/ruby/2.0.0/gems/activesupport-3.2.11/lib/active_support/inflector/methods.rb:229:in `constantize'
/app/vendor/bundle/ruby/2.0.0/gems/activesupport-3.2.11/lib/active_support/core_ext/string/inflections.rb:54:in `constantize'
/app/vendor/bundle/ruby/2.0.0/gems/activerecord-3.2.11/lib/active_record/migration.rb:538:in `load_migration'
/app/vendor/bundle/ruby/2.0.0/gems/activerecord-3.2.11/lib/active_record/migration.rb:533:in `migration'
/app/vendor/bundle/ruby/2.0.0/gems/activerecord-3.2.11/lib/active_record/migration.rb:528:in `migrate'
/app/vendor/bundle/ruby/2.0.0/gems/activerecord-3.2.11/lib/active_record/migration.rb:720:in `block (2 levels) in migrate'
/app/vendor/bundle/ruby/2.0.0/gems/activerecord-3.2.11/lib/active_record/migration.rb:775:in `call'
/app/vendor/bundle/ruby/2.0.0/gems/activerecord-3.2.11/lib/active_record/migration.rb:775:in `block in ddl_transaction'
/app/vendor/bundle/ruby/2.0.0/gems/activerecord-3.2.11/lib/active_record/connection_adapters/abstract/database_statements.rb:192:in `transaction'
/app/vendor/bundle/ruby/2.0.0/gems/activerecord-3.2.11/lib/active_record/transactions.rb:208:in `transaction'
/app/vendor/bundle/ruby/2.0.0/gems/activerecord-3.2.11/lib/active_record/migration.rb:775:in `ddl_transaction'
/app/vendor/bundle/ruby/2.0.0/gems/activerecord-3.2.11/lib/active_record/migration.rb:719:in `block in migrate'
/app/vendor/bundle/ruby/2.0.0/gems/activerecord-3.2.11/lib/active_record/migration.rb:700:in `each'
/app/vendor/bundle/ruby/2.0.0/gems/activerecord-3.2.11/lib/active_record/migration.rb:700:in `migrate'
/app/vendor/bundle/ruby/2.0.0/gems/activerecord-3.2.11/lib/active_record/migration.rb:570:in `up'
/app/vendor/bundle/ruby/2.0.0/gems/activerecord-3.2.11/lib/active_record/migration.rb:551:in `migrate'
/app/vendor/bundle/ruby/2.0.0/gems/activerecord-3.2.11/lib/active_record/railties/databases.rake:179:in `block (2 levels) in <top (required)>'

以下是我的Devise创建用户方法的全文,该方法似乎导致了此问题.

class AddDeviseToCustomers < ActiveRecord::Migration
def self.up
change_table(:customers) do |t|
  ## Database authenticatable
  t.string :email,:null => false,:default => ""
  t.string :encrypted_password,:default => ""

  ## Recoverable
  t.string   :reset_password_token
  t.datetime :reset_password_sent_at

  ## Rememberable
  t.datetime :remember_created_at

  ## Trackable
  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   :confirmation_token
  t.datetime :confirmed_at
  t.datetime :confirmation_sent_at

  ## Confirmable

  #t.string   :unconfirmed_email # Only if using reconfirmable

  ## Lockable
  # t.integer  :Failed_attempts,:default => 0 # Only if lock strategy is :Failed_attempts
  # t.string   :unlock_token # Only if unlock strategy is :email or :both
  # t.datetime :locked_at

  ## Token authenticatable
  # t.string :authentication_token


  # Uncomment below if timestamps were not included in your original model.
  # t.timestamps

    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,:authentication_token,:unique => true
  end
end
end

这一切都在heroku上的pgsql服务器上.
提前致谢