rename task to project_task and task_user to project_task_user; create project_task_category, fix bug in create project method

backend/modules/task/views/project-task-category/create.php

@@ -0,0 +1,18 @@
+<?php
+
+use yii\helpers\Html;
+
+/* @var $this yii\web\View */
+/* @var $model backend\modules\task\models\ProjectTaskCategory */
+
+$this->title = 'Создание категории задач';
+$this->params['breadcrumbs'][] = ['label' => 'Project Task Categories', 'url' => ['index']];
+$this->params['breadcrumbs'][] = $this->title;
+?>
+<div class="project-task-category-create">
+
+    <?= $this->render('_form', [
+        'model' => $model,
+    ]) ?>
+
+</div>