Updating Compose documentation

- Split out commands into individual pages for maintainability
- Add full usage in commands pages for usability
- Updated description of the run command
- adding in Aanand's comment

Signed-off-by: Mary Anthony <mary@docker.com>

docs/reference/kill.md

@@ -0,0 +1,23 @@
+<!--[metadata]>
++++
+title = "kill"
+description = "Forces running containers to stop."
+keywords = ["fig, composition, compose, docker, orchestration, cli,  kill"]
+[menu.main]
+parent = "smn_compose_cli"
++++
+<![end-metadata]-->
+
+# kill
+
+```
+Usage: kill [options] [SERVICE...]
+
+Options:
+-s SIGNAL         SIGNAL to send to the container. Default signal is SIGKILL.
+```
+
+Forces running containers to stop by sending a `SIGKILL` signal. Optionally the
+signal can be passed, for example:
+
+    $ docker-compose kill -s SIGINT