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

Makefile

@@ -0,0 +1,41 @@
+.DEFAULT_GOAL := help
+
+COMPOSE = docker-compose -f docker-compose.yml -f docker-compose.override.yml
+
+.PHONY: setup
+setup:  ## setup project
+	@mkdir -p priv/plts
+	@mix do local.rebar --force, local.hex --force
+	@mix do deps.get, deps.compile
+	@mix dialyzer --plt
+
+.PHONY: check_format
+check_format:  ## run format checker
+	@mix format --check-formatted
+
+.PHONY: credo
+credo:  ## run credo
+	@mix credo suggest --strict --format=flycheck
+
+.PHONY: dialyzer
+dialyzer:  ## run dialyzer
+	@mix dialyzer --no-check --quiet --ignore-exit-status --format short
+
+.PHONY: static_code_analysis
+static_code_analysis: check_format credo dialyzer  ## run static code analysis
+
+.PHONY: test
+test:  ## run tests
+	@mix test --cover --trace --slowest 10
+
+.PHONY: compose_up
+compose_up:  ## start containers for this service
+	@$(COMPOSE) up -d
+
+.PHONY: compose_test
+compose_test:  ## run tests in containers
+	@$(COMPOSE) run -e MIX_ENV=test --entrypoint make app test
+
+.PHONY: help
+help:
+	@grep -E '^[a-zA-Z_-]+:.*?## .*$$' $(MAKEFILE_LIST) | sort | awk 'BEGIN {FS = ":.*?## "}; {printf "\033[36m%-30s\033[0m %s\n", $$1, $$2}'