ruby on rails - Capistrano and EC2: Don't know how to build task 'db:migrate' -

when run command

cap deploy:cold 

then in deployment process these errors:

*** [err :: myapp.com] rake aborted! *** [err :: myapp.com] *** [err :: myapp.com] don't know how build task 'db:migrate' *** [err :: myapp.com] *** [err :: myapp.com] *** [err :: myapp.com] (see full trace running task --trace) *** [err :: myapp.com] 

then checked deployed - went releases folder , there these files:

license          revision  lib  public  tmp readme.markdown  rakefile  log  spec    urbanairship.gemspec 

what happened rest (like app folder example)?

edit: deploy file:

set :stages, %w(production staging) set :default_stage, "devel" require 'capistrano/ext/multistage' set :application, "myapp" set :repository, "git@github.com:name/myapp.git" set :scm, :git  set :deploy_to, "/opt/bitnami/apache2/htdocs/myapp" set :use_sudo, :false set :normalize_asset_timestamps, false  before "deploy", "check_production"