rake db：migrate error不知道如何構建任務'rails_env'

Question

運行rake db：migrate時出現錯誤。我最近添加了一個寶石gcm_on_rails後，只有我得到的錯誤。

rake aborted! 
Don't know how to build task 'rails_env' 

Tasks: TOP => db:migrate => db:load_config 

請幫

rake aborted! 
    Don't know how to build task 'rails_env' 
    /Users/.rvm/gems/ruby-1.9.2-p320@global/gems/rake-0.9.2.2/lib/rake/task_manager.rb:49:in `[]' 
    /Users/.rvm/gems/ruby-1.9.2-p320@global/gems/rake-0.9.2.2/lib/rake/task.rb:60:in `lookup_prerequisite' 
    /Users/.rvm/gems/ruby-1.9.2-p320@global/gems/rake-0.9.2.2/lib/rake/task.rb:56:in `block in prerequisite_tasks' 
    /Users/test/.rvm/gems/ruby-1.9.2-p320@global/gems/rake-0.9.2.2/lib/rake/task.rb:56:in `collect' 
    /Users/.rvm/gems/ruby-1.9.2-p320@global/gems/rake-0.9.2.2/lib/rake/task.rb:56:in `prerequisite_tasks' 
    /Users/.rvm/gems/ruby-1.9.2-p320@global/gems/rake-0.9.2.2/lib/rake/task.rb:174:in `invoke_prerequisites' 
    /Users/.rvm/gems/ruby-1.9.2-p320@global/gems/rake-0.9.2.2/lib/rake/task.rb:157:in `block in invoke_with_call_chain' 
    /Users/.rvm/rubies/ruby-1.9.2-p320/lib/ruby/1.9.1/monitor.rb:201:in `mon_synchronize' 
    /Users/.rvm/gems/ruby-1.9.2-p320@global/gems/rake-0.9.2.2/lib/rake/task.rb:151:in `invoke_with_call_chain' 
    /Users/.rvm/gems/ruby-1.9.2-p320@global/gems/rake-0.9.2.2/lib/rake/task.rb:176:in `block in invoke_prerequisites' 
    /Users/.rvm/gems/ruby-1.9.2-p320@global/gems/rake-0.9.2.2/lib/rake/task.rb:174:in `each' 
    /Users/.rvm/gems/ruby-1.9.2-p320@global/gems/rake-0.9.2.2/lib/rake/task.rb:174:in `invoke_prerequisites' 
    /Users/.rvm/gems/ruby-1.9.2-p320@global/gems/rake-0.9.2.2/lib/rake/task.rb:157:in `block in invoke_with_call_chain' 
    /Users/.rvm/rubies/ruby-1.9.2-p320/lib/ruby/1.9.1/monitor.rb:201:in `mon_synchronize' 
    /Users/.rvm/gems/ruby-1.9.2-p320@global/gems/rake-0.9.2.2/lib/rake/task.rb:151:in `invoke_with_call_chain' 
    /Users/.rvm/gems/ruby-1.9.2-p320@global/gems/rake-0.9.2.2/lib/rake/task.rb:144:in `invoke' 
    /Users/.rvm/gems/ruby-1.9.2-p320@global/gems/rake-0.9.2.2/lib/rake/application.rb:116:in `invoke_task' 
    /Users/.rvm/gems/ruby-1.9.2-p320@global/gems/rake-0.9.2.2/lib/rake/application.rb:94:in `block (2 levels) in top_level' 
    /Users/.rvm/gems/ruby-1.9.2-p320@global/gems/rake-0.9.2.2/lib/rake/application.rb:94:in `each' 
    /Users/.rvm/gems/ruby-1.9.2-p320@global/gems/rake-0.9.2.2/lib/rake/application.rb:94:in `block in top_level' 
    /Users/.rvm/gems/ruby-1.9.2-p320@global/gems/rake-0.9.2.2/lib/rake/application.rb:133:in `standard_exception_handling' 
    /Users/.rvm/gems/ruby-1.9.2-p320@global/gems/rake-0.9.2.2/lib/rake/application.rb:88:in `top_level' 
    /Users/.rvm/gems/ruby-1.9.2-p320@global/gems/rake-0.9.2.2/lib/rake/application.rb:66:in `block in run' 
    /Users/.rvm/gems/ruby-1.9.2-p320@global/gems/rake-0.9.2.2/lib/rake/application.rb:133:in `standard_exception_handling' 
    /Users/.rvm/gems/ruby-1.9.2-p320@global/gems/rake-0.9.2.2/lib/rake/application.rb:63:in `run' 
    /Users/.rvm/gems/ruby-1.9.2-p320@global/gems/rake-0.9.2.2/bin/rake:33:in `<top (required)>' 
    /Users/test/.rvm/gems/ruby-1.9.2-p320@global/bin/rake:19:in `load' 
    /Users/test/.rvm/gems/ruby-1.9.2-p320@global/bin/rake:19:in `<main>' 
    Tasks: TOP => db:migrate => db:load_config 

Answer 1

對於使用在寶石中指定的rake任務，我在我的應用程序控制器添加下面的代碼。這是造成這個問題。 當我刪除它，其工作正常。

require 'rake' 
Rake::Task.clear 
MyAPP::Application.load_tasks