Added missing dependency

app/package.json

@@ -36,6 +36,7 @@
     "redux-thunk": "^2.3.0",
     "resize-observer-polyfill": "^1.5.0",
     "riek": "^1.1.0",
+    "socket.io-client": "^2.1.1",
     "url-parse": "^1.4.3",
     "webtorrent": "^0.102.4"
   },