account for file:// when resolving app root

lib/src/lifecycle/Application.ts

@@ -123,7 +123,17 @@ export default class Application {
      * @type string
      */
     get app_root() {
-        return path.resolve(this.injector.make(Scaffolding).base_dir, 'app')
+        let base_dir = this.injector.make(Scaffolding).base_dir
+        if ( base_dir.startsWith('file://') ) {
+            base_dir = base_dir.slice(7)
+        }
+
+        const resolved = path.resolve(base_dir, 'app')
+        if ( resolved.startsWith('/') ) {
+            return `file://${resolved}`
+        } else {
+            return resolved
+        }
     }
 
     /**