Do not leave containers behind after matrix-postgres-cli usage

roles/matrix-server/templates/usr-local-bin/matrix-postgres-cli.j2

@@ -1,3 +1,9 @@
 #!/bin/bash
 
-docker run --env-file={{ matrix_environment_variables_data_path }}/env-postgres-pgsql-docker -it --link=matrix-postgres:postgres postgres:9.6.3-alpine psql -h postgres
+docker run \
+	-it \
+	--rm \
+	--env-file={{ matrix_environment_variables_data_path }}/env-postgres-pgsql-docker \
+	--link=matrix-postgres:postgres \
+	{{ docker_postgres_image }} \
+	psql -h postgres