add licence header
diff --git a/webpack.config.release.js b/webpack.config.release.js
index bf6a536..4bdedde 100644
--- a/webpack.config.release.js
+++ b/webpack.config.release.js
@@ -1,3 +1,14 @@
+// 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.
var webpack = require('webpack');
var path = require('path');
