rake db: migrate ne fonctionne pas pour moi

Question

Je reçois cette erreur

 
rake db:migrate (in 
    /Users/john/Sites/my_app) rake aborted! 
    Don't know how to build task 
    'db:migrate' 

Quand je trace l'erreur que je reçois

rake aborted! Don't know how to build task 'db:migrate' 
/usr/local/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:1728:in `[]' 
/usr/local/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:2050:in `invoke_task' 
/usr/local/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:2029:in `top_level' 
/usr/local/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:2029:in `each' 
/usr/local/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:2029:in `top_level' 
/usr/local/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:2068:in `standard_exception_handling' 
/usr/local/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:2023:in `top_level' 
/usr/local/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:2001:in `run' 
/usr/local/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:2068:in `standard_exception_handling' 
/usr/local/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:1998:in `run' 
/usr/local/lib/ruby/gems/1.8/gems/rake-0.8.7/bin/rake:31 
/usr/local/bin/rake:19:in `load' /usr/local/bin/rake:19 

Mon Rakefile est

require(File.join(File.dirname(__FILE__), 'config', 'boot')) 

require 'rake' 
require 'rake/testtask' 
require 'rake/rdoctask' 

Answer 1

Pour Ruby on Rails 2.3 vous devriez avoir la ligne supplémentaire suivante à la fin de votre Rakefile:

require 'tasks/rails'