 up an instance of DatabaseHelper, which is our local
    implementation of the SQLiteOpenHelper class. It calls <code>getWritableDatabase()</code>, 
    which handles creating/opening a database for us.</p>
    <p><code>close()</code> just closes the database, releasing resources related to the 
    connection.</p>
    <p><code>createNote()</code> takes strings for the title and body of a new note,
    then creates that note in the database. Assuming the new note is created successfully, the
    method als