title: Add a row to a matrix
body: <p>I have a matrix <code>A</code> like</p>
  
  <pre><code>1 2 3 4 5
  6 7 8 9 0
  </code></pre>
  
  <p>and I want to expand it with a row of ones to get</p>
  
  <pre><code>1 1 1 1 1
  1 2 3 4 5
  6 7 8 9 0 
  </code></pre>
  
  <p>I create the row of ones with </p>
  
  <pre><code>col_size = size(A, 2); 
  ones_row = ones(1, col_size);
  </code></pre>
  
  <p>How can I add my <code>ones_row</code> to the matrix? </p>