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

priv/docker/postgres/init.sql

@@ -1,2 +1,5 @@
 CREATE EXTENSION "uuid-ossp";
 CREATE EXTENSION "pg_stat_statements";
+CREATE EXTENSION "btree_gist";
+CREATE DATABASE wabanex_dev TEMPLATE postgres;
+CREATE DATABASE wabanex_test TEMPLATE wabanex_dev;