doc: add ThreadSafeFunction to main README (#513)

KevinEady · mhdawson · commit d9d991bbc9ef · 2019-07-18T15:34:37.000-04:00
PR-URL: #513 Reviewed-By: Gabriel Schulhof <gabriel.schulhof@intel.com> Reviewed-By: NickNaso <nicoladelgobbo@gmail.com> Reviewed-By: Michael Dawson <michael_dawson@ca.ibm.com>
diff --git a/README.md b/README.md
@@ -106,6 +106,7 @@ The following is the documentation for node-addon-api.
  - [Async Operations](doc/async_operations.md)
     - [AsyncWorker](doc/async_worker.md)
     - [AsyncContext](doc/async_context.md)
+ - [Thread-safe Functions](doc/threadsafe_function.md)
  - [Promises](doc/promises.md)
  - [Version management](doc/version_management.md)
 
