Add delete functionality

override.php

@@ -33,22 +33,29 @@
 
 // Check if an ID is provided
 $id = optional_param('id', null, PARAM_INT);
+$delete = optional_param('delete', null, PARAM_BOOL);
 
 // Set the PAGE URL (and mandatory context). Note the ID being recorded, this is important.
 $PAGE->set_context(context_system::instance());
 $PAGE->set_url(new moodle_url('/admin/tool/heartbeat/override.php', ['id' => $id]));
 
 // Instantiate a persistent object if we received an ID. Typically receiving an ID
 // means that we are going to be updating an object rather than creating a new one.
-$persistent = null;
+$override = null;
 
 if (!empty($id)) {
-    $persistent = new override($id);
+    $override = new override($id);
+}
+
+// Handle deletion
+if (!empty($id) && !empty($delete) && $delete) {
+    $override->delete();
+    redirect(new moodle_url('/admin/tool/heartbeat/status.php'));
 }
 
 // Create the form instance. We need to use the current URL and the custom data.
 $customdata = [
-    'persistent' => $persistent,
+    'persistent' => $override,
     'usermodified' => $USER->id // For the hidden userid field.
 ];
 
@@ -61,12 +68,12 @@
     try {
         if (empty($data->id)) {
             // If there is no ID we need to create a new persistent.
-            $persistent = new Override(0, $data);
-            $persistent->create();
+            $override = new Override(0, $data);
+            $override->create();
         } else {
             // If we have an ID we need to update the persistent.
-            $persistent->from_record($data);
-            $persistent->update();
+            $override->from_record($data);
+            $override->update();
         }
         \core\notification::success(get_string('changessaved'));
     } catch (Exception $e) {