rake aborted! You have already activated rake 10.1.0, but your Gemfile requires rake 10.0.3. Using bundle exec may solve this.

問題：

wyy@wyy:~/moumentei-master$ rake db:create
rake aborted!
You have already activated rake 10.1.0, but your Gemfile requires rake 10.0.3. Using bundle exec may solve this.

解決：

Remove rake 10.1.0 gem

 gem uninstall rake and remove 10.0.2 version of rake gem