You're looking for an issue tracking system / bugtracker. Try the Issues tab on github. You create an issue/task that needs to be done, assign it to a developer

You're looking for an issue tracking system / bugtracker. Try the Issues tab on github. You create an issue/task that needs to be done, assign it to a developer, and ask them to update the issue's details as he/she progresses. I am not that familiar with GitHub, so I can't give you specific instructions or examples, but the project I'm working on uses Mantis for this, and it works a treat - we integrated it with SVN and now svn commits create new Product Versions, revision commit messages are automatically posted as issue comments + issues get marked as "resolved" if applicable, changelogs for latest changes, roadmaps for future plans, etc.