Improve project usage (#6)

1. Ignore unnecessary files, such as `pgcli` log/history, and extra `docker-compose` definitions.
2. Add `Makefile` with common tasks.
3. Add git pre-commit hook to ensure project is always properly formatted.
4. Add [`btree_gist`][0] extension to `postgres`.

Reviewed-on: #6

[0]: https://www.postgresql.org/docs/14/btree-gist.html

.drone.yml

@@ -5,8 +5,8 @@ name: test
 
 trigger:
   event:
-    include:
-      - pull_request
+    - push
+    - pull_request
 
 steps:
   - name: database healthcheck