Just merged the group-chat branch into master, it will be available in our next release which will most likely be 1.0.0.
There are some breaking changes and schema changes in this merge.
The upgrade script will go through all the chat messages and assign them to rooms. This might take a while depending on how many chats messages there are in the system. The upgrade script should show the progress in the console.
For all the changes check out this PR https://github.com/NodeBB/NodeBB/pull/3968/files
1.0.0 finally it's getting serious... xD
Oh wauw, that looks amazing. Is there a ability to name group "rooms"?
@baris A good idea is that like telegram indicate that a message has been read by the user or not!
@baris you rockstar! This is such a killer feature!
@sanatisharif I can see that working out to be honest.
@julian have you guys thought about doing something like nodechat.org? This feature is so killer, you could easily make a successful sister project
Nice. I guess many people will like this. I hope it can be disabled also.
I'm assuming each person only sees posts from after they're added to the room?
Perhaps @psychobunny needs to work some of his "-user- was added to the room" magic between posts.
Looking good @baris. 
@julian I'm still waiting for the hidden features @psychobunny is releasing sooner or later,
@Kowlin said:
@exodo any reason you want a option to disable it?
Maybe not a disable, but instead make a max participant value. If the forum admin sets it to 2, then it would be no different than now.
I really want the feature. I cannot count the number of times I have had a chat going and then had to either backfire things to another person, or take it to another medium (Skype/hangouts) in order to get a group chat going.
I guess 
Poor guy..