Add button to get to MyGroups (view_my_groups or path #/groups)

src/components/structures/MyGroups.js

@@ -102,7 +102,7 @@ export default withMatrixClient(React.createClass({
         }
 
         return <div className="mx_MyGroups">
-            <SimpleRoomHeader title={ _t("Groups") } />
+            <SimpleRoomHeader title={ _t("Groups") } icon="img/icons-groups.svg" />
             <div className='mx_MyGroups_joinCreateBox'>
                 <div className="mx_MyGroups_createBox">
                     <div className="mx_MyGroups_joinCreateHeader">

src/components/views/elements/GroupsButton.js

@@ -0,0 +1,39 @@
+/*
+Copyright 2017 New Vector Ltd
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+import React from 'react';
+import sdk from '../../../index';
+import PropTypes from 'prop-types';
+import { _t } from '../../../languageHandler';
+
+const GroupsButton = function(props) {
+    const ActionButton = sdk.getComponent('elements.ActionButton');
+    return (
+        <ActionButton action="view_my_groups"
+            label={ _t("Groups") }
+            iconPath="img/icons-groups.svg"
+            size={props.size}
+            tooltip={props.tooltip}
+        />
+    );
+};
+
+GroupsButton.propTypes = {
+    size: PropTypes.string,
+    tooltip: PropTypes.bool,
+};
+
+export default GroupsButton;