[doc] Explicitely name the module in which we define schema to distinguish it from entities.
--- a/doc/book/en/B0012-schema-definition.en.txt Tue Apr 14 11:30:14 2009 -0700
+++ b/doc/book/en/B0012-schema-definition.en.txt Tue Apr 14 17:16:43 2009 -0700
@@ -6,7 +6,9 @@
An entity type is defined by a Python class which inherits from `EntityType`.
The class definition contains the description of attributes and relations
for the defined entity type.
-The class name corresponds to the entity type name.
+The class name corresponds to the entity type name. It is exepected to be
+defined in the module ``mycube.schema``.
+
For example ::