Make sure to set the right rootDir for app/api

Change-Id: Id4210ac6b392b8f565119fcd5b27a5b5de339e66
diff --git a/polygerrit-ui/app/api/tsconfig.json b/polygerrit-ui/app/api/tsconfig.json
index 4d8ecac..037e4f2 100644
--- a/polygerrit-ui/app/api/tsconfig.json
+++ b/polygerrit-ui/app/api/tsconfig.json
@@ -1,5 +1,8 @@
 {
   "extends": "../../../plugins/tsconfig-plugins-base.json",
+  "compilerOptions": {
+    "rootDir": ".",
+  },
   "include": [
     "**/*",
   ],