Fixing unitialized map

model/profile.go

@@ -284,6 +284,7 @@ func (p *Profile) ProcessInvite(gci *protocol.GroupChatInvite, peerHostname stri
 	group.InitialMessage = gci.GetInitialMessage()[:]
 	group.Accepted = false
 	group.Owner = peerHostname
+	group.Attributes = make(map[string]string)
 	p.AddGroup(group)
 }