add human-readable studygroup names for CSV headings if option is enabled in admin page

booking.admin.inc

@@ -231,6 +231,14 @@ function booking_admin()
     ),
     '#default_value' => variable_get('booking_publish_readinggroups', 0)
   );
+
+  $form['features']['booking_friendly_csv_groupnames'] = array(
+    '#type' => 'radios',
+    '#title' => t('Use human-friendly study group names in CSV export?'),
+    '#description' => t('Select whether to use descriptions for study group columns when exporting CSV. If No, internal database field names are used.'),
+    '#options' => array(0 => t('No'), t('Yes')),
+    '#default_value' => variable_get('booking_friendly_csv_groupnames', 0),
+  );  
   
   $form['misc'] = array(
     '#type' => 'fieldset',