serial: should be owned by 'dialout' group

base/etc/group

@@ -1,2 +1,3 @@
 root:x:0:
 adm:x:1:local
+dialout:x:2:local

base/etc/passwd

@@ -1,4 +1,5 @@
 root:x:0:0:Administrator:/home/root:/bin/sh:fancy
 adm:x:1:1:Administrators:/tmp:/bin/false:nope
+dialout:x:2:2:Serial Users:/tmp:/bin/false:nope
 local:x:1000:1000:Local User:/home/local:/bin/sh:fancy
 guest:x:1001:1001:Guest User:/home/guest:/bin/sh:fancy

kernel/arch/x86_64/serial.c

@@ -159,6 +159,9 @@ static fs_node_t * serial_device_create(int port) {
 		}
 	}
 
+	pty->slave->gid = 2; /* dialout group */
+	pty->slave->mask = 0660;
+
 	return pty->slave;
 }