Update Sahara 'How to Participate' doc
Update Sahara 'How to Participate' doc

Update 'How to Participate' document in connection with the latest
changes

Change-Id: I02d4de7bd33b245706ea8da05be4dcd6bd738874

esikachev/sahara-backup,zhujzhuo/Sahara,henaras/sahara,ekasitk/sahara,bigfootproject/sahara,redhat-openstack/sahara,tellesnobrega/sahara,esikachev/sahara-backup,bigfootproject/sahara,henaras/sahara,crobby/sahara,openstack/sahara,redhat-openstack/sahara,zhangjunli177/sahara,zhangjunli177/sahara,zhujzhuo/Sahara,tellesnobrega/sahara,egafford/sahara,egafford/sahara,ekasitk/sahara,crobby/sahara,redhat-openstack/sahara,crobby/sahara,bigfootproject/sahara,openstack/sahara,matips/iosr-2015,matips/iosr-2015,esikachev/sahara-backup,henaras/sahara,matips/iosr-2015,zhangjunli177/sahara,ekasitk/sahara,zhujzhuo/Sahara