make the default id be the timestamp of the comic

model/Comic.php

@@ -25,6 +25,8 @@ class Comic {
                 $this->{$key} = $value;
             }
          }
+         
+         if (!isset($this->id) && isset($this->date)) { $this->id = $this->date; }
     }
   
     /**

test/model/TestComic.php

@@ -19,7 +19,8 @@ class TestComic extends PHPUnit_Framework_TestCase {
                 array("2006-01-01.txt"),
                 array(new Comic(array('date' => '2006-01-01',
                                       'title' => '2006-01-01',
-                                      'copy' => "")))
+                                      'copy' => "",
+                                      'id' => strtotime('2006-01-01'))))
             )
         ); 
     }