Put username on the upper right corner.

src/App.tsx

@@ -8,6 +8,7 @@ import AppBar from 'material-ui/AppBar';
 import Drawer from 'material-ui/Drawer';
 import IconButton from 'material-ui/IconButton';
 import { List, ListItem } from 'material-ui/List';
+import FlatButton from 'material-ui/FlatButton';
 import Subheader from 'material-ui/Subheader';
 import Divider from 'material-ui/Divider';
 import ActionCode from 'material-ui/svg-icons/action/code';
@@ -75,7 +76,7 @@ class App extends React.Component {
   };
 
   props: {
-    credentials?: store.CredentialsData;
+    credentials?: store.CredentialsType;
   };
 
   constructor(props: any) {
@@ -101,6 +102,10 @@ class App extends React.Component {
   }
 
   render() {
+    const username = (this.props.credentials && this.props.credentials.value) ?
+      <FlatButton label={this.props.credentials.value.credentials.email} />
+       : undefined;
+
     return (
       <MuiThemeProvider muiTheme={muiTheme}>
         <HashRouter>
@@ -108,6 +113,7 @@ class App extends React.Component {
           <AppBar
             title={C.appName}
             iconElementLeft={<IconButton onClick={this.toggleDrawer}><NavigationMenu /></IconButton>}
+            iconElementRight={username}
           />
           <Drawer
             docked={false}