Add required attribute to CRUD form dropdown

app/model/PageModel.php

@@ -67,7 +67,7 @@ class PageModel extends Model {
 		// Pull sections from cache
 		$sections = Db::getSections();
 
-		return [0 => 'Select section'] + array_combine(
+		return ['' => 'Select section'] + array_combine(
 			array_column($sections, 'id'),
 			array_column($sections, 'title')
 		);

app/views/admin/crud/create.php

@@ -43,7 +43,7 @@
 
 	<?php } else if ($attribute[1] == 'dropdown') { ?>
 
-					<select name="<?= $name; ?>" class="custom-select">
+					<select name="<?= $name; ?>" class="custom-select" <?= $required; ?>>
 		<?php foreach($this->dropdownData[$key] as $dropdownKey => $value) { ?>
 						<option value="<?= $dropdownKey; ?>"><?= $value; ?></option>
 		<?php } ?>

app/views/admin/crud/edit.php

@@ -45,7 +45,7 @@
 
 	<?php } else if ($attribute[1] == 'dropdown') { ?>
 
-					<select name="<?= $name; ?>" class="custom-select">
+					<select name="<?= $name; ?>" class="custom-select" <?= $required; ?>>
 		<?php foreach($this->dropdownData[$key] as $dropdownKey => $value) { ?>
 						<option value="<?= $dropdownKey; ?>"
 							<?= $this->model->$name == $dropdownKey ? 'selected' : ''; ?>>