Added GPL license.

Author: louiscyphre

context.xml

@@ -1,20 +1,21 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <!--
-  Licensed to the Apache Software Foundation (ASF) under one or more
-  contributor license agreements.  See the NOTICE file distributed with
-  this work for additional information regarding copyright ownership.
-  The ASF licenses this file to You 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.
---><!-- The contents of this file will be loaded for each web application --><Context>
+  ~     webapp-otc - an online collaboration tool .
+  ~     Copyright (C) 2017 Ilia Butvinnik and Michael Goldman
+  ~
+  ~     This program is free software: you can redistribute it and/or modify
+  ~     it under the terms of the GNU General Public License as published by
+  ~     the Free Software Foundation, either version 3 of the License, or
+  ~     (at your option) any later version.
+  ~
+  ~     This program is distributed in the hope that it will be useful,
+  ~     but WITHOUT ANY WARRANTY; without even the implied warranty of
+  ~     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+  ~     GNU General Public License for more details.
+  ~
+  ~     You should have received a copy of the GNU General Public License
+  ~     along with this program.  If not, see <http://www.gnu.org/licenses/>.
+  --><!-- The contents of this file will be loaded for each web application --><Context>
 
     <!-- Default set of monitored resources -->
     <WatchedResource>WEB-INF/web.xml</WatchedResource>