gem: integrate change from pull request

Assuming you're using Bundler, you can specify the repository and branch to use for the gem in your Gemfile (it also supports specifying a tag or a reference hash, but a branch should work for your case). In this case, it might look something like:

gem 'carrierwave-video', :git => 'git://github.com/elja/carrierwave-video.git', :branch => 'patch-1'

or, more concisely:

gem 'carrierwave-video', :github => 'elja/carrierwave-video', :branch => 'patch-1'

This isn't a great long-term solution, since the branch is unlikely to continue to keep up to date properly, and might disappear, so you should probably switch back to the default as soon as the pull request is resolved.