db: README documentation

README.rst

@@ -44,6 +44,10 @@ In the source directory (whether cloned or from the tarball) run
 bot. Alternately, you can just run the ``sopel.py`` file in the source
 directory.
 
+Database Support
+----------------
+Sopel leverages SQLAlchemy to support the following database types: SQLite, MySQL, PostgreSQL, MSSQL, Oracle, Firebird, and Sybase. By default Sopel will use a SQLite database in the current configuration directory, but alternative databases can be configured with the following config options: db_type, db_filename (SQLite only), db_driver, db_user, db_pass, db_host, db_port, and db_name.
+
 Adding modules
 --------------
 The easiest place to put new modules is in ``~/.sopel/modules``. Some newer