Add command to remove project activities after one year

app/Console/ProjectActivityArchiveCommand.php

@@ -0,0 +1,21 @@
+<?php
+
+namespace Kanboard\Console;
+
+use Symfony\Component\Console\Input\InputInterface;
+use Symfony\Component\Console\Output\OutputInterface;
+
+class ProjectActivityArchiveCommand extends BaseCommand
+{
+    protected function configure()
+    {
+        $this
+            ->setName('projects:archive-activities')
+            ->setDescription('Remove project activities after one year');
+    }
+
+    protected function execute(InputInterface $input, OutputInterface $output)
+    {
+        $this->projectActivityModel->cleanup(strtotime('-1 year'));
+    }
+}