Fix edge-case where tag creation failed

Fixes #154
Fixes #163

Author: mikebronner

CHANGELOG.md

@@ -4,7 +4,7 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](http://keepachangelog.com/en/1.0.0/)
 and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.html).
 
-## [0.3.1] - 10 Sep 2018
+## [0.3.1] - 7 Oct 2018
 ### Changed
 - use of `cache()` helper method to `app("cache")` to allow for better Lumen compatibility. Thanks @nope7777!
 
@@ -16,6 +16,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
 
 ### Fixed
 - use of custom pagination name.
+- edge-case where tag creation failed.
 
 ## [0.3.0] - 10 Sep 2018
 ### Added

src/Traits/Caching.php

@@ -79,9 +79,12 @@ protected function makeCacheKey(
     protected function makeCacheTags() : array
     {
         $eagerLoad = $this->eagerLoad ?? [];
-        $model = $this->model ?? $this;
-        $query = $this->query ?? app('db')->query();
-
+        $model = $this->model instanceof Model
+            ? $this->model
+            : $this;
+        $query = $this->query instanceof Builder
+            ? $this->query
+            : app('db')->query();
         $tags = (new CacheTags($eagerLoad, $model, $query))
             ->make();