update form to ask previous sw question

booking.constants.inc

@@ -130,7 +130,19 @@ function _get_tshirt_options() {
 	return $options_array;
 }
 
-
+/**
+ * Helper function to provide a list of options for the previous study week count field of the registration form
+ */
+function _get_previous_sw_options() {
+	$options_array = array();
+  $options_array[''] = '';
+  
+  for ($i = 0; $i < 6; $i++) {
+    $options_array[$i] = $i;
+  }
+  
+	return $options_array;
+}
 
 /**
  * Helper function to look up description of studygroup role