the type of our <tt>id</tt> column,
we are indicating that we would like SQLite to manage this column and 
assign a unique numeric key to each row we insert automatically.
We also add the keyword <tt>UNIQUE</tt> to indicate that we will not 
allow SQLite to insert two rows with the same value for <tt>name</tt>.<br />
<br />
Now instead of creating the table <tt>Pals</tt> above, we create
a table called <tt>Follows</tt> with two integer columns
<code>from_id</code> and <code>to_id</code> and a constraint on 