feat: add .env.example for all

src/postgres/.env.example

@@ -1 +1,14 @@
-POSTGRES_PASSWORD=
+# PostgreSQL Version
+POSTGRES_VERSION=17.6
+
+# Database user
+POSTGRES_USER=postgres
+
+# Database password
+POSTGRES_PASSWORD=postgres
+
+# Database name
+POSTGRES_DB=postgres
+
+# Port to bind to on the host machine
+POSTGRES_PORT=5432