upgrade getting started instruction [#352]

README.md

@@ -13,9 +13,25 @@ writing documentation.
 
 ## Getting Started
 
-You can install DBot's dependencies, configure and run the bot for the first
-time with the following command:
+To get started with DBot, you first need to decide on a database system to use.
+DBot uses the [databank](http://github.com/e14n/databank) library, and each
+module can be configured to use any database driver databank supports in its
+respective config.json file. There is currently no default database driver
+option.
+
+The default for all modules is the 'redis' driver, and you can simply install
+the Redis server to get going.
+
+Once you have that set up, you can install DBot's dependencies, configure and 
+run the bot for the first time with the following command:
 
 ```
 sh install.sh
 ```
+
+## Upgrading
+
+If you have used a previous version of DBot, then you can migrate most data
+using the [dbot-migrate](https://github.com/reality/dbot-migrate) module.
+Instructions on how to run this are included in the repository - remember to
+remove db.json after migration, otherwise the instance will be slow!