Run Jekyll:
bundle exec jekyll serve
Before you deploy, commit your changes to any working branch except the gh-pages one then run the following command:
bin/deploy
Important note: Chalk does not support the standard way of Jekyll hosting on GitHub Pages. You need to deploy your working branch with the bin/deploy script. This is because Chalk uses Jekyll plugins that aren't supported by GitHub pages.
View this for more info about automated deployment with Circle CI.