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

README.md

@@ -0,0 +1,11 @@
+# Training Log (TRAILOG)
+
+[![Build Status](https://drone.dubas.dev/api/badges/joao.dubas/ex_trainer/status.svg?ref=refs/heads/main)](https://drone.dubas.dev/joao.dubas/ex_trainer)
+
+## Setup
+
+## Execute
+
+## Tests
+
+## Next steps