Add Docker Compose + Postgres to devcontainer for Codespaces support (#324)

Author: Copilot

.devcontainer/devcontainer.json

@@ -2,21 +2,30 @@
 // README at: https://github.com/devcontainers/templates/tree/main/src/typescript-node
 {
 	"name": "GitHub Copilot Metrics Viewer Dev Environment",
-	// Or use a Dockerfile or Docker Compose file. More info: https://containers.dev/guide/dockerfile
-	"image": "mcr.microsoft.com/devcontainers/typescript-node:1-22-bookworm",
+	"dockerComposeFile": "docker-compose.yml",
+	"service": "app",
+	"workspaceFolder": "/workspaces/copilot-metrics-viewer",
 	"features": {
 		"ghcr.io/devcontainers/features/azure-cli:1": {},
 		"ghcr.io/devcontainers/features/github-cli:1": {}
 	},
 
-	// Features to add to the dev container. More info: https://containers.dev/features.
-	// "features": {},
-
-	// Use 'forwardPorts' to make a list of ports inside the container available locally.
-	// "forwardPorts": [],
+	// Forward ports for the app and PostgreSQL.
+	"forwardPorts": [3000, 5432],
+	"portsAttributes": {
+		"3000": {
+			"label": "App (Nuxt)",
+			"onAutoForward": "notify"
+		},
+		"5432": {
+			"label": "PostgreSQL",
+			"onAutoForward": "silent"
+		}
+	},
 
-	// Use 'postCreateCommand' to run commands after the container is created.
-	"postCreateCommand": "npm install && npm run serve"
+	// Install dependencies on container creation. The database schema is initialized
+	// automatically on first app startup via initSchema() in server/storage/db.ts.
+	"postCreateCommand": "npm install",
 
 	// Configure tool-specific properties.
 	// "customizations": {},

.devcontainer/docker-compose.yml

@@ -0,0 +1,32 @@
+services:
+  app:
+    image: mcr.microsoft.com/devcontainers/typescript-node:1-22-bookworm
+    volumes:
+      - ..:/workspaces/copilot-metrics-viewer:cached
+    environment:
+      - DATABASE_URL=postgresql://metrics_user:metrics_password@db:5432/copilot_metrics
+    command: sleep infinity
+    depends_on:
+      db:
+        condition: service_healthy
+
+  db:
+    image: postgres:15-alpine
+    restart: unless-stopped
+    # Development-only credentials — not suitable for production use.
+    environment:
+      POSTGRES_DB: copilot_metrics
+      POSTGRES_USER: metrics_user
+      POSTGRES_PASSWORD: metrics_password
+    ports:
+      - "5432:5432"
+    volumes:
+      - postgres_data:/var/lib/postgresql/data
+    healthcheck:
+      test: ["CMD-SHELL", "pg_isready -U metrics_user -d copilot_metrics"]
+      interval: 5s
+      timeout: 3s
+      retries: 5
+
+volumes:
+  postgres_data: