Add make restart and make stop commands for managing the docker container

Per issue #62. Also adds docs on using these commands.

Author: ddworken

docker/Makefile

@@ -30,6 +30,13 @@ serve: env-file-exists ca-key-exists build
 	docker run -d --restart unless-stopped -v $(CURDIR)/example-keybaseca-volume:/mnt:rw ca:latest docker/entrypoint-server.sh
 	@echo "Started CA bot service in the background... Use `docker ps` and `docker logs` to monitor it"
 
+# Stop the service
+stop:
+	docker kill `docker ps -q --filter ancestor=ca`
+
+# Restart the service (useful if you updated env.sh)
+restart: stop serve
+
 # Wipe all data
 clean: confirm-clean reset-permissions
 	@# Sudo since it is likely owned by another use since it was written from a docker container

docs/getting_started.md

@@ -65,3 +65,10 @@ kssh root@server                        # If in {TEAM}.ssh.root_everywhere
 ```
 
 We recommend building kssh yourself and distributing the binary among your team (perhaps in Keybase Files!). 
+
+## Updating environment variables
+
+If you update any environment variables, it is necessary to restart the keybaseca service. This can be done 
+by running `make restart`. Note that it is not required to re-run `make generate`. 
+
+Note that this means `kssh` will not work for a brief period of time while the container restarts.