add shell -r (to run as root)

shell

 #!/bin/bash
 
+if [ "$1" = "-r" ] ; then
+	shift
+	user="-u root"
+else
+	user=
+fi
+
 CTR="$1"
 
 if [ -z "$CTR" ] ; then
@@ -9,4 +16,4 @@ fi
 
 set -ex
 fig up -d "$CTR"
-docker exec -t -i -- "$CTR" /bin/bash
+docker exec -t -i $user -- "$CTR" /bin/bash