Add background image to auth pages

src/components/views/auth/VectorAuthPage.js

@@ -0,0 +1,45 @@
+/*
+Copyright 2019 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.
+*/
+
+'use strict';
+
+const React = require('react');
+import sdk from 'matrix-react-sdk/lib/index';
+
+module.exports = React.createClass({
+    displayName: 'VectorAuthPage',
+
+    statics: {
+        replaces: 'AuthPage',
+    },
+
+    render: function() {
+        const AuthFooter = sdk.getComponent('auth.AuthFooter');
+
+        const style = {
+            background: 'center/cover fixed url(../../themes/riot/img/backgrounds/valley.jpg)',
+        };
+
+        return (
+            <div className="mx_AuthPage" style={style}>
+                <div className="mx_AuthPage_modal">
+                    { this.props.children }
+                </div>
+                <AuthFooter />
+            </div>
+        );
+    },
+});