Fix missing appPath

Author: zinserjan

packages/react-scripts/config/paths.js

@@ -51,6 +51,7 @@ function getServedPath(appPackageJson) {
 // config after eject: we're in ./config/
 module.exports = {
   dotenv: resolveApp('.env'),
+  appPath: resolveApp('.'),
   appBuild: resolveApp('build'),
   appPublic: resolveApp('public'),
   appHtml: resolveApp('public/index.html'),