feat(infra): add PostgreSQL support as database backend option

Implement PostgreSQL as an alternative database backend alongside
MongoDB. Users can now select postgres via SHELLHUB_DATABASE environment
variable.

- Add PostgreSQL configuration env vars (username, password, database)
- Create docker-compose.postgres.yml with postgres:18.0 service
- Update bin/utils to recognize 'postgres' as valid database option
- Configure healthcheck for PostgreSQL service

Author: heiytor

.env

@@ -36,6 +36,10 @@ SHELLHUB_AUTO_SSL=false
 
 SHELLHUB_DATABASE=mongo
 
+SHELLHUB_POSTGRES_USERNAME=admin
+SHELLHUB_POSTGRES_PASSWORD=admin
+SHELLHUB_POSTGRES_DATABASE=main
+
 # The domain of the server.
 # NOTICE: Required only if automatic HTTPS is enabled.
 # VALUES: A valid domain name

bin/utils

@@ -73,7 +73,7 @@ COMPOSE_FILE="docker-compose.yml"
 
 SHELLHUB_DATABASE=${SHELLHUB_DATABASE:-mongo}
 case "$SHELLHUB_DATABASE" in
-    mongo)
+    mongo|postgres)
         COMPOSE_FILE="${COMPOSE_FILE}:docker-compose.${SHELLHUB_DATABASE}.yml"
         ;;
     *)

docker-compose.postgres.yml

@@ -0,0 +1,24 @@
+services:
+  postgres:
+    image: postgres:18.0
+    command: postgres -c io_method=io_uring
+    security_opt:
+      # Disable seccomp to allow io_uring syscalls (io_uring_setup, io_uring_enter, io_uring_register)
+      # which are blocked by Docker's default seccomp profile for security reasons.
+      - seccomp=unconfined
+    healthcheck:
+      start_period: 90s
+      interval: 5s
+      timeout: 5s
+      retries: 5
+      test: ["CMD-SHELL", "pg_isready -U ${SHELLHUB_POSTGRES_USERNAME} -d ${SHELLHUB_POSTGRES_DATABASE}"]
+    environment:
+      - POSTGRES_USER=${SHELLHUB_POSTGRES_USERNAME}
+      - POSTGRES_PASSWORD=${SHELLHUB_POSTGRES_PASSWORD}
+      - POSTGRES_DB=${SHELLHUB_POSTGRES_DATABASE}
+    networks:
+      - shellhub
+  api:
+    depends_on:
+      postgres:
+        condition: service_healthy