docs: Add Docker Compose file to simplify contributions (#532)

README.md

@@ -82,4 +82,10 @@ To run the test suite, linter and code coverage:
 npm run cover
 ```
 
-The test suite will try and create a new database named pgboss. The [config.json](test/config.json) file has the default credentials to connect to postgres. 
+The test suite will try and create a new database named pgboss. The [config.json](test/config.json) file has the default credentials to connect to postgres.
+
+The [Docker Compose](docker-compose.yaml) file can be used to start a local postgres instance for testing:
+
+```bash
+docker-compose up -d
+```

docker-compose.yaml

@@ -0,0 +1,15 @@
+services:
+  db:
+    image: postgres:16
+    ports:
+      - 5432:5432
+    volumes:
+      - db_volume:/var/lib/postgresql/data
+    environment:
+      - POSTGRES_DB=pgboss
+      - POSTGRES_NAME=pgboss
+      - POSTGRES_USER=postgres
+      - POSTGRES_PASSWORD=postgres
+
+volumes:
+  db_volume: