Revisited the persistence layer.

Simplified schema to focus on user and node.
Now possible to have sqlite via ODBC and/or mysql support, and select using configuration file.
Updated demo example.

library/model/src/content/cms_node.e

@@ -3,8 +3,8 @@ note
 			CMS abstraction for CMS content entity, named "node".
 		]"
 	status: "draft"
-	date: "$Date$"
-	revision: "$Revision$"
+	date: "$Date: 2015-01-27 19:15:02 +0100 (mar., 27 janv. 2015) $"
+	revision: "$Revision: 96542 $"
 
 class
 	CMS_NODE
@@ -83,8 +83,8 @@ feature -- Access
 	author: detachable CMS_USER
 			-- Author of current node.
 
-	collaborators: detachable LIST[CMS_USER]
-			-- Users contributed to current Node.
+--	collaborators: detachable LIST[CMS_USER]
+--			-- Users contributed to current Node.
 
 feature -- status report
 
@@ -177,18 +177,18 @@ feature -- Element change
 			auther_set: author = u
 		end
 
-	add_collaborator (a_user: CMS_USER)
-			-- Add collaborator `a_user' to the collaborators list.
-		local
-			lst: like collaborators
-		do
-			lst := collaborators
-			if lst = Void then
-				create {ARRAYED_SET [CMS_USER]} lst.make (1)
-				collaborators := lst
-			end
-			lst.force (a_user)
-		end
+--	add_collaborator (a_user: CMS_USER)
+--			-- Add collaborator `a_user' to the collaborators list.
+--		local
+--			lst: like collaborators
+--		do
+--			lst := collaborators
+--			if lst = Void then
+--				create {ARRAYED_SET [CMS_USER]} lst.make (1)
+--				collaborators := lst
+--			end
+--			lst.force (a_user)
+--		end
 
 note
 	copyright: "2011-2014, Javier Velilla, Jocelyn Fiat, Eiffel Software and others"