add readme

modules/concurrency/README.md

@@ -1,9 +1,21 @@
-# README: containers
+# Concurrency Module
 
-## Brief
+The Concurrency module provides a set of classes and functions to help with multithreaded programming. It includes utilities for managing threads, synchronizing data access, and handling asynchronous tasks.
 
-containers provides .. <one line description>
+## Spinner Component
 
-## Detailed description
+One of the key components of the Concurrency module is the `Spinner` class. The `Spinner` class provides a simple way to run a task in a separate thread and stop it when necessary.
 
-Provide more details on the functionality, API usage, etc
+### Usage
+
+To use the `Spinner` class, you need to create a subclass and implement the `spinOnce` method. This method will be called repeatedly in a separate thread when the spinner is started.
+Check the [example](examples/spinner_example.cpp) for more details.
+
+### Stopping the Spinner
+
+The `Spinner` class provides a `stop` method to stop the spinner. You can also add a stop callback that will be called when the spinner is stopped.
+Check the [test](tests/spinner_tests.cpp) for more details.
+
+### Thread Safety
+
+The `Spinner` class is thread-safe. You can safely call `start`, `stop`, and `addStopCallback` from multiple threads without additional synchronization.