Hosting your Jekyll site on GitHub Pages can certainly save a lot of headache. Unless something goes wrong. Since your only interface to it is git push, being able to reproduce the GitHub environment can be the only way to solve a bug.
There are two gems you will need to align, Jekyll version 0.11.0 and Liquid version 2.2.2. If you are uncertain about your current versions, gem list can show you.
$ gem list|egrep 'liquid|jekyll'
jekyll (0.11.0)
liquid (2.2.2)
If they do not match, you will need to remove them before installing the correct versions.
gem uninstall jekyll liquid
gem install liquid -v 2.2.2
gem install jekyll -v 0.11.0
After the installation has completed you should now have the same environment as on GitHub Pages. Just be sure to run Jekyll with the same arguments!
$ jekyll --pygments --no-lsi --safe