Update README (#157)

* Update README

Signed-off-by: Anas Abou Allaban <[email protected]>

Author: Anas Abou Allaban

README.md

@@ -18,6 +18,21 @@ sudo pip3 install -U setuptools pip
 sudo pip3 install colcon-ros-bundle
 ```
 
+# How it works
+
+`colcon bundle` performs the following steps to bundle your package:
+
+1. Parse package dependencies through your `package.xml`.
+1. Add dependencies to the install list for each installer.
+1. Run installs in the following order:
+    1. `apt`
+    1. `pip`
+    1. `pip3`
+1. Run the following transforms:
+    1. Update the shebangs of scripts to use `#!/usr/bin/env`.
+1. Bundle your local workspace and dependencies into a standalone ROS workspace.
+The bundled workspace follows the format defined in [`BUNDLE_FORMAT.md`](BUNDLE_FORMAT.md).
+
 # Building a bundle with `colcon bundle`
 
 To build your ROS workspace into a bundle execute: