1110418 - Added documentation on publishing repository groups

https://bugzilla.redhat.com/show_bug.cgi?id=1110418
Two suggestions on this line.

1. Escape each tag itself so that it's not one long escaped value which includes the commas
2. It seems these are double-ly escaped. Once with quotes and once with double backticks. I recommend using one or the other, but not both.