添加获取微信支持的门店类目表

创建门店时,必须填入微信支持格式的门店类目, 所以需要先获得支持的门店类目
点击查看[微信创建门店文档](https://mp.weixin.qq.com/wiki?action=doc&id=mp1444378120&t=0.3682459036774999#mdlmb)

src/POI/POI.php

@@ -33,6 +33,18 @@ class POI extends AbstractAPI
     const API_LIST = 'http://api.weixin.qq.com/cgi-bin/poi/getpoilist';
     const API_UPDATE = 'http://api.weixin.qq.com/cgi-bin/poi/updatepoi';
     const API_DELETE = 'http://api.weixin.qq.com/cgi-bin/poi/delpoi';
+    const API_GET_CATEGORIES = 'http://api.weixin.qq.com/cgi-bin/poi/getwxcategory';
+
+
+    /**
+     * Get POI supported categories.
+     *
+     * @return \EasyWeChat\Support\Collection
+     */
+    public function getCategories()
+    {
+        return $this->parseJSON('get', [self::API_GET_CATEGORIES]);
+    }
 
     /**
      * Get POI by ID.

tests/POI/POIPOITest.php

@@ -26,6 +26,17 @@ public function getPOI()
         return $POI;
     }
 
+    /**
+     * Test getCategories().
+     */
+    public function testGetCategories()
+    {
+        $POI = $this->getPOI();
+
+        $response = $POI->getCategories();
+        $this->assertStringStartsWith(POI::API_GET_CATEGORIES, $response['api']);
+    }
+
     /**
      * Test get().
      */