fix(postgres): Fix postgres suddenly failing after their 'patch' release

See
https://github.com/docker-library/postgres/pull/658#pullrequestreview-336007842

docker-compose.yml

@@ -61,6 +61,8 @@ services:
   postgres:
     << : *restart_policy
     image: 'postgres:9.6'
+    environment:
+      POSTGRES_HOST_AUTH_METHOD: 'trust'
     volumes:
       - 'sentry-postgres:/var/lib/postgresql/data'
   zookeeper: