Fixes the profiles-plugin

An error was introduced with 7f75bb9, which uses special vars. This is the
fix.
Merge pull request #3299 from apoxa/fix-profiles

Fix for the profile plugin.
Add CONTRIBUTING.md file general structure
Categories of issues in oh-my-zsh (work-in-progress)
Format categories of issues in oh-my-zsh (still WIP)

Conflicts:
	CONTRIBUTING.md