Add related projects to top-level README (#279)

README.md

@@ -100,5 +100,12 @@ brew install needle
 
 The linked document uses a somewhat real example to explain what the dependency injection pattern is, and its benefits.
 
+## Related projects
+
+If you like Needle, check out other related open source projects from our team:
+- [Swift Concurrency](https://github.com/uber/swift-concurrency): a set of concurrency utility classes used by Uber, inspired by the equivalent [java.util.concurrent](https://docs.oracle.com/javase/8/docs/api/java/util/concurrent/package-summary.html) package classes.
+- [Swift Abstract Class](https://github.com/uber/swift-abstract-class): a light-weight library along with an executable that enables compile-time safe abstract class development for Swift projects.
+- [Swift Common](https://github.com/uber/swift-common): common libraries used by this set of Swift open source projects.
+
 ## License
 [![FOSSA Status](https://app.fossa.io/api/projects/git%2Bgithub.com%2Fuber%2Fswift-concurrency.svg?type=large)](https://app.fossa.io/projects/git%2Bgithub.com%2Fuber%2Fswift-concurrency?ref=badge_large)