improve README.md

-# LDAP-Admin
+# ldap-admin
 
-## abstract
+A tool to manage users in an LDAP dictionary or a MySQL database.
 
-Some ruby code for LDAP directory management.
+_unfinished_
 
-## requires
+## Synopsis
 
-ruby 1.8
+The DN's used in ``tester.rb`` are obviously not applicable for other sites.
+Additionally they do not reflect the current structure used here at
+**weird-web-workers.org**.
 
-## status
+To test anything you need to have a directory and use fitting DN's for
+testing.
 
-discontinued
\ No newline at end of file
+## Description
+
+### What is there
+
+ * Various data-models (user, group, mailAccount, mailALias, etc.)
+ * These might be stored in different storage backends
+ * These storage engines are queried with different query languages.
+ * The model specifies _which_ data is queried.
+ * The storage engine decides _how_ the data is queried.
+
+> **Conflict**: With ldap it is difficult to separate the _which_ from the
+> _how_.
+>
+> **Possible solution: Some kind of factory that initializes the concrete
+> database by the class of the model and the class of the storage engine.
+>
+> **Alternative**: Instead of a separate factory it might be feasable to
+> create a generic database class with a method to create an instance by a
+> given model.
+>
+> **Problem**: Then the database class has to know the initialization
+> information for the associated model, which is an implementation detail
+> of the model in fact. So this information should come from somewhere else
+> but probably not from the model, because it probably also needs
+> implementation details of the database class.
+>
+> **Maybe**: it is possible to do something by nameing conventions. But it
+> might be cleaner to have a separate configuration file for each storage
+> backend in which the necessary informations for the queries of the models
+> can be configured.
+
+A yaml file for this might look like this: (ldap.yml)
+
+    ldap: # => wenn es pro Datenbank ne eigenen datei gibt ist das nicht noetig
+     host: host.one.virtual
+     port: 389
+     queries:
+      User:
+       baseDn: ou=user,o=system,dc=weird-web-workers,dc=org
+       filter: (objectClass=posixAccount)
+      Group:
+       baseDn: ou=group,o=system,dc=weird-web-workers,dc=org
+       filter: (objectClass=posixGroup)
+    
+    ...
+
+As an alternative of a single mapping file we could create one mapping file
+for each mode / storage backend combination. These would be very small and
+fast readable.
+
+Filesystem structure:
+
+    model - user.rb
+          - group.rb
+          - site.rb
+          - mailalias_role.rb
+          - mailalias_person.rb
+          - mailaccount.rb
+    data - ldap.rb
+    data - config - ldap.yml
+    adapter - ldap.rb
+            - config - ldap - user.yml
+                            - group.yml
+                            - site.yml
+                            - mailalias_role.yml
+                            - mailalias_person.yml
+                            - mailaccount.yml
+
+## Requirements
+
+ * A running test dictionary or database
+ * Ruby
+
+## Dependencies
+
+unknown
+
+## Contributing
+
+Just email me.
+
+## License
+
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+    
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+    
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+## Author
+
+Georg Hopp <georg@steffers.org>