Issue #27:Fix homepage is now signup

src/App.js

@@ -15,6 +15,7 @@ function App() {
   return (
     <HashRouter>
       <Header />
+      <Route path="/" component={SignUp} />
       <Route path="/visualize/:id" component={VisualizeForm} />
       <Route path="/create" component={CreateForm} />
       <Route path="/answer/:id" component={AnswerForm} />