Added a bit of documentation.

README.md

@@ -3,6 +3,12 @@
 [![License](https://img.shields.io/badge/license-MIT-blue.svg)](https://raw.githubusercontent.com/PolyMathOrg/DataFrame/master/LICENSE)
 [![Pharo version](https://img.shields.io/badge/Pharo-8.0-%23aac9ff.svg)](https://pharo.org/download)
 
+Implementation of the command design pattern with the following objectives:
+- Simple model of commands
+- Ease reusability of commands accross multiple tools / framework
+- Instance of commands can be modified (e.g., name, description, etc...)
+- Pluging custom user-command made easy
+
 ## Install
 
 ```
@@ -11,3 +17,13 @@ Metacello new
 	baseline: 'Commander2';
 	load
 ```
+
+## Example
+`Commander2-ContactBook` package contains an example of Commander2 usage in the context of a Spec application.
+
+The following code should be checked when learning how to use the framework:
+
+- `CmContactBookCommand` and subclasses are the definition of commands required by the example application.
+- `CmContactBookPresenter class>>#buildCommandsGroupWith:forRoot:` This method is the entry point to describe commands available to your Spec presenter. One can learn how to build group of commands from this method.
+- `CmContactBookPresenter>>#initializeWidgets` This method shows how to inject a Spec's `MenuPresenter` built from a command group in your presenter.
+- `CmContactBookPresenter>>#initializeWindow:` This method shows how to bind the shortcuts defined by your command group to your Spec presenter.