undefined method database_authenticatable' for #<ActiveRecord::ConnectionAdapters::PostgreSQLAdapter::TableDefinition:0xd715388>
移行は次のとおりです。
class DeviseCreateUsers < ActiveRecord::Migration
  def self.up
    create_table(:users) do |t|
      t.database_authenticatable :null => false
      t.recoverable
      t.rememberable
      t.trackable
      t.timestamps
    end
    add_index :users, :email,                :unique => true
    add_index :users, :reset_password_token, :unique => true
  end
  def self.down
    drop_table :users
  end
end