Update Dockerfiles to include ASF license header (#25)
diff --git a/core/ruby2.5Action/Dockerfile b/core/ruby2.5Action/Dockerfile
index 4fd4ff0..c253b23 100644
--- a/core/ruby2.5Action/Dockerfile
+++ b/core/ruby2.5Action/Dockerfile
@@ -1,3 +1,19 @@
+#
+# 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.
+#
FROM ruby:2.5
# install dependencies
