Add License Headers for Apache Rat

Change-Id: I9eba838b16eed0e30c93c210eff6131c489beade
diff --git a/asterix-bad/src/main/resources/lang-extension/lang.txt b/asterix-bad/src/main/resources/lang-extension/lang.txt
index b433f5f..2001988 100644
--- a/asterix-bad/src/main/resources/lang-extension/lang.txt
+++ b/asterix-bad/src/main/resources/lang-extension/lang.txt
@@ -1,3 +1,22 @@
+//
+// 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.
+//
+
 import org.apache.asterix.bad.lang.statement.BrokerDropStatement;
 import org.apache.asterix.bad.lang.statement.ChannelDropStatement;
 import org.apache.asterix.bad.lang.statement.ChannelSubscribeStatement;