Add files upload

app/Templates/task_upload.php

@@ -0,0 +1,10 @@
+<div class="page-header">
+    <h2><?= t('Attach a document') ?></h2>
+</div>
+
+<form action="?controller=task&amp;action=upload&amp;task_id=<?= $task['id'] ?>" method="post" enctype="multipart/form-data">
+    <input type="file" name="files[]" multiple />
+    <div class="form-actions">
+        <input type="submit" value="<?= t('Save') ?>" class="btn btn-blue"/>
+    </div>
+</form>