SEBA-421 Print error messages to stderr, not stdout;
Add Makefile

Change-Id: I7d4285a343d723ff3fc2aa2f7b1abfb806de8966
diff --git a/Makefile b/Makefile
new file mode 100644
index 0000000..3f64f7d
--- /dev/null
+++ b/Makefile
@@ -0,0 +1,23 @@
+# Copyright 2019-present Open Networking Foundation
+#
+# 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.
+
+# Configure shell
+SHELL = bash -e -o pipefail
+
+all: test
+
+test: test-unit
+
+test-unit:
+	tox