Fix roomId handling

app/src/components/App.js

@@ -1,4 +1,5 @@
 import React, { useEffect, Suspense } from 'react';
+import { useParams} from 'react-router';
 import { connect } from 'react-redux';
 import PropTypes from 'prop-types';
 import JoinDialog from './JoinDialog';
@@ -13,6 +14,8 @@ const App = (props) =>
 		room
 	} = props;
 
+	let { id } = useParams();
+
 	useEffect(() =>
 	{
 		Room.preload();
@@ -23,7 +26,7 @@ const App = (props) =>
 	if (!room.joined)
 	{
 		return (
-			<JoinDialog />
+			<JoinDialog roomId={id} />
 		);
 	}
 	else