Add VS Code debugger configuration

.vscode/launch.json

@@ -0,0 +1,28 @@
+{
+	// Use IntelliSense to learn about possible attributes.
+	// Hover to view descriptions of existing attributes.
+	// For more information, visit: https://go.microsoft.com/fwlink/?linkid=830387
+	"version": "0.2.0",
+	"configurations": [
+		{
+			"name": "Launch debugging in Firefox",
+			"type": "firefox",
+			"request": "launch",
+			"reAttach": true,
+			"url": "http://localhost:3000/",
+			"webRoot": "${workspaceFolder}"
+		},
+		{
+			"name": "Attach",
+			"type": "firefox",
+			"request": "attach"
+		},
+		{
+			"name": "Launch WebExtension",
+			"type": "firefox",
+			"request": "launch",
+			"reAttach": true,
+			"addonPath": "${workspaceFolder}"
+		}
+	]
+}