Update README.md

Author: wz1000

README.md

@@ -73,7 +73,7 @@ main = runServer $ ServerDefinition
 ```
 
 Whilst `Reactor.hs` shows how a reactor design can be used to handle all
-requests on a single thread, such in a way that we could then execute them on
+requests on a separate thread, such in a way that we could then execute them on
 multiple threads without blocking server communication. They can be installed
 from source with