Update README.md

Author: sksamuel

README.md

@@ -9,3 +9,22 @@ Scales is available for both maven and sbt.
 
 * [SCCT](https://github.com/SCCT/scct)
 * [Jacoco4sbt](https://github.com/sbt/jacoco4sbt)
+
+## License
+```
+This software is licensed under the Apache 2 license, quoted below.
+
+Copyright 2013 Stephen Samuel
+
+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.
+```