Update CONTRIBUTING.md to port contribution flow section from EE doc
Update CONTRIBUTING.md to port contribution flow section from EE doc
dreampet/gitlab,iiet/iiet-git,axilleas/gitlabhq,mmkassem/gitlabhq,stoplightio/gitlabhq,stoplightio/gitlabhq,jirutka/gitlabhq,axilleas/gitlabhq,jirutka/gitlabhq,dreampet/gitlab,axilleas/gitlabhq,jirutka/gitlabhq,iiet/iiet-git,dreampet/gitlab,dreampet/gitlab,iiet/iiet-git,mmkassem/gitlabhq,mmkassem/gitlabhq,jirutka/gitlabhq,stoplightio/gitlabhq,axilleas/gitlabhq,iiet/iiet-git,stoplightio/gitlabhq,mmkassem/gitlabhq