Update README.md

Author: SethTisue

README.md

@@ -6,6 +6,8 @@ This is an sbt 1.x plugin for building Scala modules.
 
 * [scala-async](https://github.com/scala/scala-async)
 * [scala-collection-compat](https://github.com/scala/scala-collection-compat)
+* [scala-collection-contrib](https://github.com/scala/scala-collection-contrib)
+* [scala-continuations](https://github.com/scala/scala-continuations)
 * [scala-java8-compat](https://github.com/scala/scala-java8-compat)
 * [scala-parallel-collections](https://github.com/scala/scala-parallel-collections)
 * [scala-parser-combinators](https://github.com/scala/scala-parser-combinators)