加载 PostgreSQL 数据库结构报错 “undefined method `values_at' for "gem install pg":String"

[zeroday]

想研究一下https://github.com/daqing/rabel的源码，在本机用Vagrant搭载环境时出现各种问题，现在在加载数据库结构报错。

agrant@vagrant-ubuntu-ruby2:/vagrant/www/rabel$ RAILS_ENV=production bundle exec rake db:setup --trace
** Invoke db:setup (first_time)
** Invoke db:schema:load_if_ruby (first_time)
** Invoke db:create (first_time)
** Invoke db:load_config (first_time)
** Execute db:load_config
** Invoke rails_env (first_time)
** Execute rails_env
** Execute db:create
rake aborted!
undefined method `values_at' for "gem install pg":String
/home/vagrant/.rvm/gems/ruby-2.0.0-p247/gems/activerecord-3.2.17/lib/active_record/railties/databases.rake:638:in `configs_for_environment'
/home/vagrant/.rvm/gems/ruby-2.0.0-p247/gems/activerecord-3.2.17/lib/active_record/railties/databases.rake:62:in `block (2 levels) in <top (required)>'
/home/vagrant/.rvm/gems/ruby-2.0.0-p247/gems/rake-10.1.1/lib/rake/task.rb:236:in `call'
/home/vagrant/.rvm/gems/ruby-2.0.0-p247/gems/rake-10.1.1/lib/rake/task.rb:236:in `block in execute'
/home/vagrant/.rvm/gems/ruby-2.0.0-p247/gems/rake-10.1.1/lib/rake/task.rb:231:in `each'
/home/vagrant/.rvm/gems/ruby-2.0.0-p247/gems/rake-10.1.1/lib/rake/task.rb:231:in `execute'
/home/vagrant/.rvm/gems/ruby-2.0.0-p247/gems/rake-10.1.1/lib/rake/task.rb:175:in `block in invoke_with_call_chain'
/home/vagrant/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/monitor.rb:211:in `mon_synchronize'
/home/vagrant/.rvm/gems/ruby-2.0.0-p247/gems/rake-10.1.1/lib/rake/task.rb:168:in `invoke_with_call_chain'
/home/vagrant/.rvm/gems/ruby-2.0.0-p247/gems/rake-10.1.1/lib/rake/task.rb:197:in `block in invoke_prerequisites'
/home/vagrant/.rvm/gems/ruby-2.0.0-p247/gems/rake-10.1.1/lib/rake/task.rb:195:in `each'
/home/vagrant/.rvm/gems/ruby-2.0.0-p247/gems/rake-10.1.1/lib/rake/task.rb:195:in `invoke_prerequisites'
/home/vagrant/.rvm/gems/ruby-2.0.0-p247/gems/rake-10.1.1/lib/rake/task.rb:174:in `block in invoke_with_call_chain'
/home/vagrant/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/monitor.rb:211:in `mon_synchronize'
/home/vagrant/.rvm/gems/ruby-2.0.0-p247/gems/rake-10.1.1/lib/rake/task.rb:168:in `invoke_with_call_chain'
/home/vagrant/.rvm/gems/ruby-2.0.0-p247/gems/rake-10.1.1/lib/rake/task.rb:197:in `block in invoke_prerequisites'
/home/vagrant/.rvm/gems/ruby-2.0.0-p247/gems/rake-10.1.1/lib/rake/task.rb:195:in `each'
/home/vagrant/.rvm/gems/ruby-2.0.0-p247/gems/rake-10.1.1/lib/rake/task.rb:195:in `invoke_prerequisites'
/home/vagrant/.rvm/gems/ruby-2.0.0-p247/gems/rake-10.1.1/lib/rake/task.rb:174:in `block in invoke_with_call_chain'
/home/vagrant/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/monitor.rb:211:in `mon_synchronize'
/home/vagrant/.rvm/gems/ruby-2.0.0-p247/gems/rake-10.1.1/lib/rake/task.rb:168:in `invoke_with_call_chain'
/home/vagrant/.rvm/gems/ruby-2.0.0-p247/gems/rake-10.1.1/lib/rake/task.rb:161:in `invoke'
/home/vagrant/.rvm/gems/ruby-2.0.0-p247/gems/rake-10.1.1/lib/rake/application.rb:149:in `invoke_task'
/home/vagrant/.rvm/gems/ruby-2.0.0-p247/gems/rake-10.1.1/lib/rake/application.rb:106:in `block (2 levels) in top_level'
/home/vagrant/.rvm/gems/ruby-2.0.0-p247/gems/rake-10.1.1/lib/rake/application.rb:106:in `each'
/home/vagrant/.rvm/gems/ruby-2.0.0-p247/gems/rake-10.1.1/lib/rake/application.rb:106:in `block in top_level'
/home/vagrant/.rvm/gems/ruby-2.0.0-p247/gems/rake-10.1.1/lib/rake/application.rb:115:in `run_with_threads'
/home/vagrant/.rvm/gems/ruby-2.0.0-p247/gems/rake-10.1.1/lib/rake/application.rb:100:in `top_level'
/home/vagrant/.rvm/gems/ruby-2.0.0-p247/gems/rake-10.1.1/lib/rake/application.rb:78:in `block in run'
/home/vagrant/.rvm/gems/ruby-2.0.0-p247/gems/rake-10.1.1/lib/rake/application.rb:165:in `standard_exception_handling'
/home/vagrant/.rvm/gems/ruby-2.0.0-p247/gems/rake-10.1.1/lib/rake/application.rb:75:in `run'
/home/vagrant/.rvm/gems/ruby-2.0.0-p247/gems/rake-10.1.1/bin/rake:33:in `<top (required)>'
/home/vagrant/.rvm/gems/ruby-2.0.0-p247/bin/rake:23:in `load'
/home/vagrant/.rvm/gems/ruby-2.0.0-p247/bin/rake:23:in `<main>'
/home/vagrant/.rvm/gems/ruby-2.0.0-p247/bin/ruby_noexec_wrapper:14:in `eval'
/home/vagrant/.rvm/gems/ruby-2.0.0-p247/bin/ruby_noexec_wrapper:14:in `<main>'
Tasks: TOP => db:setup => db:schema:load_if_ruby => db:create