added Codespaces support (#2290)

.devcontainer/devcontainer.json

@@ -0,0 +1,28 @@
+{
+  "name": "VirtualTabletop.io",
+  "forwardPorts": [
+    9229,
+    8272
+  ],
+  "portsAttributes": {
+    "9229": {
+      "label": "Node.js Debugger",
+      "onAutoForward": "ignore"
+    },
+    "8272": {
+      "label": "VirtualTabletop.io",
+      "onAutoForward": "notify",
+      "visibility": "public"
+    }
+  },
+  "postCreateCommand": "bash .devcontainer/setup.sh",
+  "postStartCommand": "npm run debug",
+  "customizations": {
+    "vscode": {
+      "settings": {
+        "debug.node.autoAttach": "on"
+      },
+      "extensions": []
+    }
+  }
+}

.devcontainer/setup.sh

@@ -0,0 +1,4 @@
+#!/bin/bash
+sed -r "s/http:\/\/localhost:([0-9]+)/https:\/\/${CODESPACE_NAME}-\\1.app.github.dev/;s/VirtualTabletop.io/Codespaces VTT/;s/(allowPublicLibraryEdits.: )false/\\1true/" config.template.json > config.json
+npm install
+gh codespace ports visibility 8272:public -c $CODESPACE_NAME

.vscode/launch.json

@@ -0,0 +1,15 @@
+{
+  "version": "0.2.0",
+  "configurations": [
+    {
+      "type": "node",
+      "request": "attach",
+      "name": "VirtualTabletop.io",
+      "address": "localhost",
+      "port": 9229,
+      "restart": true,
+      "skipFiles": ["<node_internals>/**"]
+    }
+  ]
+}
+