Update README.md

README.md

@@ -61,7 +61,7 @@ Following steps will get you started with creating a database and populating it
 * Important: The server should be already started on your virtual machine -- you do not need to start it. However, the following two help pages discuss how to start the
    server: [Creating a database cluster](http://www.postgresql.org/docs/current/static/creating-cluster.html) and [Starting the server](http://www.postgresql.org/docs/current/static/server-start.html)
 
-* PostgreSQL server has a default superuser called **postgres**. You can do everything under that username, or you can create a different username for yourself. If you run a command (say `createdb`) without any options, it uses the same username that you are logged in under (i.e., `vagrant`). However, if you haven't created a PostgreSQL user with that name, the command will fail. You can either create a user (by logging in as the superuser), or run everything as a superuser (typically with the option: **-U postgres**).
+* PostgreSQL server has a default superuser called **postgres**. You can do everything under that username, or you can create a different username for yourself. If you run a command (say `createdb`) without any options, it uses the same username that you are logged in under (i.e., `ubuntu`). However, if you haven't created a PostgreSQL user with that name, the command will fail. You can either create a user (by logging in as the superuser), or run everything as a superuser (typically with the option: **-U postgres**).
 
 * After the server has started, the first step is to **create** a database, using the **createdb** command. PostgreSQL automatically creates one database for its own purpose, called **postgres**. It is preferable you create a different database for your data. Here are more details on **createdb**: 
    http://www.postgresql.org/docs/current/static/tutorial-createdb.html