Added TIP box with information about the `--database` switch for the...

Added TIP box with information about the `--database` switch for the application generator in the "Getting Started" guide

railties/guides/source/getting_started.textile

@@ -258,6 +258,8 @@ development:
 
 Change the username and password in the +development+ section as appropriate.
 
+TIP: You don't have to update the database configurations manually. If you had a look at the options of application generator, you have seen that one of them is named <tt>--database</tt>. It lets you choose an adapter for couple of most used relational databases. You can even run the generator repeatedly: <tt>cd .. && rails new blog --database=mysql</tt>. When you confirm the overwriting of the +config/database.yml+ file, your application will be configured for MySQL instead of SQLite.
+
 h4. Creating the Database
 
 Now that you have your database configured, it's time to have Rails create an empty database for you. You can do this by running a rake command: