add rake db:migrate as build step for rails.

mhh..., maybe say "step" instead of "phase"?

go/detect/detect.go

	&Project{"python/django", Commands{"build": "python manage.py syncdb", "run": "python manage.py runserver",
		"test": "python manage.py test"}, pythonDjango},
	&Project{"python/default", Commands{"run": "python {file}"}, pythonDefault},
	&Project{"ruby/rails", Commands{"run": "rails server", "test": "bundle exec rake test"}, rubyRails},
	&Project{"ruby/rails", Commands{"build": "bundle exec rake db:migrate", "run": "rails server",
		"test": "bundle exec rake test"}, rubyRails},
	&Project{"ruby/rake", Commands{"run": "rake", "test": "rake test"}, rubyRake},
	&Project{"ruby/default", Commands{"run": "ruby {file}"}, rubyDefault},
	&Project{"make", Commands{"run": "make", "test": "make test"}, makeDefault},