Documentation (#168)

doc/tutorials/REQUIRE.md

@@ -1,11 +1,29 @@
-The library offers a way to organize the code by creating separate source files (modules) and load them when needed by
-declaring dependencies between them.
+The library proposes a way to organize the code by creating separate source files (modules) with dependencies.
+The ({@see gpf.require.define}) API is the main entry point. 
 
-Scope is private
+A module has several properties:
+- Its scope is private: you can define variables inside it...
+- Dependencies are resolved then injected
+
+Whatever the module format you want to apply, it must always start with a call to gpf.require.define.
+No factory function is required and you know when dependant modules are loaded because of the returned promise that is
+resolved upon successful loading of dependencies. 
+
+## GPF Module
+
+```JavaScript
+gpf.require.define({
+
+}, function (require) {
+
+});
+```
 
 
 ## Asynchronous Module Definition (AMD)
 
+The [AMD](https://en.wikipedia.org/wiki/Asynchronous_module_definition) format
+
 ```JavaScript
 define("amd", ["data.json"], function (data) {
     "use strict";