Add devcontainer env

.devcontainer/devcontainer.json

@@ -0,0 +1,56 @@
+{
+  "name": "Lunchtime Web",
+  "dockerComposeFile": [
+    "../src/compose.yml",
+    "docker-compose.devcontainer.yml"
+  ],
+  "service": "devcontainer",
+  "workspaceFolder": "/workspaces/lunchtime-web",
+  "runServices": [
+    "backend",
+    "frontend",
+    "mailpit",
+    "nginx"
+  ],
+  "shutdownAction": "stopCompose",
+  "overrideCommand": false,
+  "forwardPorts": [
+    8020,
+    8025
+  ],
+  "portsAttributes": {
+    "8020": {
+      "label": "Lunchtime",
+      "onAutoForward": "openBrowser"
+    },
+    "8025": {
+      "label": "Mailpit",
+      "onAutoForward": "notify"
+    }
+  },
+  "features": {
+    "ghcr.io/devcontainers/features/python:1": {
+      "version": "3.12"
+    },
+    "ghcr.io/devcontainers/features/node:1": {
+      "version": "20"
+    }
+  },
+  "customizations": {
+    "vscode": {
+      "extensions": [
+        "ms-python.python",
+        "ms-python.vscode-pylance",
+        "dbaeumer.vscode-eslint"
+      ],
+      "settings": {
+        "python.analysis.extraPaths": [
+          "${workspaceFolder}/src/backend"
+        ],
+        "python.testing.pytestEnabled": false,
+        "typescript.tsdk": "${workspaceFolder}/src/frontend/node_modules/typescript/lib"
+      }
+    }
+  },
+  "postCreateCommand": "python -m pip install --user -r src/backend/requirements.txt && npm --prefix src/frontend ci"
+}

.devcontainer/docker-compose.devcontainer.yml

@@ -0,0 +1,8 @@
+services:
+  devcontainer:
+    image: mcr.microsoft.com/devcontainers/base:ubuntu
+    command: sleep infinity
+    volumes:
+      - ..:/workspaces/lunchtime-web:cached
+    working_dir: /workspaces/lunchtime-web
+    init: true