add docker stack ls

Signed-off-by: Akihiro Suda <suda.akihiro@lab.ntt.co.jp>
Upstream-commit: 5ce08ddfcae5ded73ef0c93c9daba7c916c21ae5
Component: engine

components/engine/docs/reference/commandline/stack_ls.md

@@ -0,0 +1,37 @@
+<!--[metadata]>
++++
+title = "stack ls"
+description = "The stack ls command description and usage"
+keywords = ["stack, ls"]
+advisory = "experimental"
+[menu.main]
+parent = "smn_cli"
++++
+<![end-metadata]-->
+
+# stack ls (experimental)
+
+```markdown
+Usage:	docker stack ls
+
+List stacks
+```
+
+Lists the stacks.
+
+For example, the following command shows all stacks and some additional information:
+
+```bash
+$ docker stack ls
+
+ID                 SERVICES
+vossibility-stack  6
+myapp              2
+```
+
+## Related information
+
+* [stack config](stack_config.md)
+* [stack deploy](stack_deploy.md)
+* [stack rm](stack_rm.md)
+* [stack tasks](stack_tasks.md)