Add Ruby example to CSPRNG table

Since there are other Ruby and Rails examples throughout the doc, adding Ruby seemed appropriate here.

Signed-off-by: Jason Frey <[email protected]>

Author: Fryguy

secure_software_development_fundamentals.md

@@ -4477,6 +4477,11 @@ Here are some examples of how to call the predictable PRNG versus a cryptographi
     <td>random</td>
     <td>os.random</td>
   </tr>
+  <tr>
+    <td>Ruby</td>
+    <td>rand (or Random.rand)</td>
+    <td>SecureRandom.rand</td>
+  </tr>
 </table>