Module directory consists of following files:

* module.php (REQUIRED):

Contains the information for the module, such as:
- version
- name
- menu entries
- sql installation queries

* navigation.xml (OPTIONAL):

Contains the navigation for the module. This file is optional and if not used,
the default page called <module_name>.php is loaded.

* Additional files:

In addition to the files above module can have as many extra files as you want.