Add copyright notice

COPYRIGHT_NOTICE

@@ -0,0 +1,13 @@
+   Copyright 2021 Equilibrium, OnFlow
+
+   This project is licensed under the Apache License, Version 2.0 (the "License");
+   you may not use the material in produced by this project 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.