Błąd w DB: Migracja "niezainicjowana stała DeviseCreateUsers"

Question

Próbuję uruchomić polecenie rake db: migrate command na Heroku i pojawia się ten problem.

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)>' 

Oto pełny tekst mojej metody tworzenia użytkowników, która wydaje się być przyczyną tego problemu.

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

Wszystko to na serwerze pgsql na heroku. Z góry dziękuję

Answer 1

Dzieje się tak, jeśli zmieniono nazwę klasy migracji i nie zmieniono nazwy pliku migracji.

Np jeśli nazwa klasy migracja

AddDeviseToCustomers 

następnie nazwa pliku migracja powinna być

201307220112_add_devise_to_customers.rb