Some refactoring and misc improvements

README.md

@@ -19,9 +19,33 @@ There is a Doxyfile at the root of the project, meaning that if you have Doxygen
 generate a complete HTML documentation that will be available in the *./doc/html/* folder.
 
 ### Dependencies:
-  * Django 1.8
-  * Pillow
+See requirements.txt
 
 The development is done with sqlite, but it is advised to set a more robust DBMS for production (Postgresql for example)
 
 
+### Misc about development
+
+#### Controlling the rights
+
+When you need to protect an object, there are three levels:
+  * Editing the object properties
+  * Editing the object various values
+  * Viewing the object
+
+Now you have many solutions in your model:
+  * You can define a `is_owned_by(self, user)`, a `can_be_edited_by(self, user)`, and/or a `can_be_viewed_by(self, user)`
+    method, each returning True is the user passed can edit/view the object, False otherwise.   
+    This allows you to make complex request when the group solution is not powerful enough.    
+    It's useful too when you want to define class-wide permissions, e.g. the club members, that are viewable only for
+    Subscribers.
+  * You can add an `owner_group` field, as a ForeignKey to Group.  Second is an `edit_groups` field, as a ManyToMany to
+    Group, and third is a `view_groups`, same as for edit.
+
+Finally, when building a class based view, which is highly advised, you just have to inherit it from CanEditPropMixin,
+CanEditMixin, or CanViewMixin, which are located in core.views. Your view will then be protected using either the
+appropriate group fields, or the right method to check user permissions.
+
+
+
+