/health endpoint

Summary: Add a simple endpoint to the server to check if it's up and running.

Reviewed By: aigoncharov

Differential Revision: D35087344

fbshipit-source-id: ec490fdb11042e7a7e4b9b944b018c4c9853ed49

desktop/flipper-server/src/startBaseServer.tsx

@@ -53,6 +53,10 @@ function startAssetServer(
     });
   });
 
+  app.get('/health', (_req, res) => {
+    res.end('flipper-ok');
+  });
+
   app.use(express.static(config.staticDir));
 
   const server = http.createServer(app);