Improve db_manager README

Author: m-kuhn

python/plugins/db_manager/README

@@ -0,0 +1,18 @@
+DB Manager
+==========
+
+Copyright (c) 2011 Giuseppe Sucameli
+
+DB Manager is a database manager core plugin for QGIS.
+It allows showing the database contents and running queries on them.
+
+At the moment DB Manager supports the following DBMS backends:
+
+- PostgreSQL/PostGIS through the psycopg2 pymodule
+- SQLite/SpatiaLite using the pyspatialite pymodule
+- GeoPackage
+- Oracle Spatial using PyQt QtSql module
+
+For more info about the project see the [QGIS
+Documentation](http://docs.qgis.org/testing/en/docs/user_manual/plugins/plugins_db_manager.html)
+or the [GSoC 2011 wiki page](http://qgis.org/wiki/DB_Manager_plugin_GSoC_2011).