Alternate way to install rails_upgrade plugin

Alternate way to install rails_upgrade plugin when getting error "ruby: No such file or directory -- script/plugin (LoadError)" while installing the plugin:

While running the command   

ruby script/plugin install git://github.com/rails/rails_upgrade.git

getting error 

ruby: No such file or directory -- script/plugin (LoadError).

Alternate way to install the plugin is to visit the site 

"https://github.com/rails/rails_upgrade"

and download the plugin.Extract the zip folder, you will get a folder named "rails-rails_upgrade-56b0337" inside folder "rails-rails_upgrade-56b0337".

Rename the inside folder from "rails-rails_upgrade-56b0337" to "rails_upgrade", copy and place the folder inside "vendor\plugins" folder. 

So Simple and your plugin is ready to be used.....