Update to follow Guard 2.0 changes

With this change, I fixed an issue with the watcher, s you no longer need the `watch` line in the template file because it will automatically watch the input file.

```ruby
# This
guard 'uglify', :input => 'app/assets/javascripts/application.js', :output => "public/javascripts/application.js" do
  watch (%r{app/assets/javascripts/application.js})
end

# Can be changed to this
guard 'uglify',
  :input => 'app/assets/javascripts/application.js',
  :output => "public/javascripts/application.js"
```