Add shell command

Author: lats1

scripts/itkdev-docker-compose

@@ -177,6 +177,9 @@ Commands:
   images:pull
                 Update/pull all docker images.
 
+  shell [service name]
+                Enter into /usr/bin/env sh inside container. E.g. itkdev-docker-compose shell phpfpm
+
   composer
                 Run composer command inside phpfpm container
 
@@ -469,6 +472,10 @@ EOF
     docker_compose down --volumes --remove-orphans
     ;;
 
+  shell)
+    docker_compose exec "$@" /usr/bin/env sh
+    ;;
+
   --help)
     usage
     exit