Add tooltip to favorite

src/components/FavoriteButton.tsx

@@ -3,6 +3,7 @@ import * as classNames from 'classnames';
 
 import FavoriteBorderIcon from '@material-ui/icons/FavoriteBorder';
 import FavoriteIcon from '@material-ui/icons/Favorite';
+import Tooltip from '@material-ui/core/Tooltip';
 import { trackPiwikEvent } from '../piwik/piwik';
 
 class FavoriteButton extends React.Component<FavoriteButtonProps, FavoriteButtonState> {
@@ -43,14 +44,18 @@ class FavoriteButton extends React.Component<FavoriteButtonProps, FavoriteButton
     render() {
         if (this.state.isFavorite) {
             return (
-                <FavoriteIcon onClick={this.handleClick}
-                    className={classNames('favorite-button-heart', 'favorite-button-heart-favorited')} />
+                <Tooltip title="Remove Favorite">
+                    <FavoriteIcon onClick={this.handleClick}
+                        className={classNames('favorite-button-heart', 'favorite-button-heart-favorited')} />
+                </Tooltip>
             );
         }
 
         return (
-            <FavoriteBorderIcon onClick={this.handleClick}
-                className={classNames('favorite-button-heart')} />
+            <Tooltip title="Add Favorite">
+                <FavoriteBorderIcon onClick={this.handleClick}
+                    className={classNames('favorite-button-heart')} />
+            </Tooltip>
         );
     }
 }