[source] base-files: add "tty" user group

[LEDE Commits]

jow pushed a commit to source.git, branch master:
https://git.lede-project.org/5523ee3459a2d346ad068ce359cdb60dcda1239d

commit 5523ee3459a2d346ad068ce359cdb60dcda1239d
Author: Jo-Philipp Wich <jo at mein.io>
AuthorDate: Sat Jun 10 20:49:10 2017 +0200

    base-files: add "tty" user group
    
    This is needed for an upcoming change to the hotplug default rules which
    will cause /dev/tty* nodes to get assigned to the "tty" group in order
    to support unprivileged user access when needed.
    
    Signed-off-by: Jo-Philipp Wich <jo at mein.io>
---
 package/base-files/files/etc/group | 1 +
 1 file changed, 1 insertion(+)

diff --git a/package/base-files/files/etc/group b/package/base-files/files/etc/group
index d366851..e8e2adf 100644
--- a/package/base-files/files/etc/group
+++ b/package/base-files/files/etc/group
@@ -1,6 +1,7 @@
 root:x:0:
 daemon:x:1:
 adm:x:4:
+tty:x:5:
 mail:x:8:
 audio:x:29:
 www-data:x:33: