Add postId function to get posts by id

Author: AndrewFeeney

README.md

@@ -51,6 +51,11 @@ WpApi::post($slug);
 
 ```
 
+```php
+WpApi::postId($id);
+
+```
+
 #### Categories
 ```php
 WpApi::categories();

src/Threesquared/LaravelWpApi/WpApi.php

@@ -60,6 +60,17 @@ public function pages($page = null)
         return $this->get('posts', ['type' => 'page', 'page' => $page]);
     }
 
+    /**
+     * Get post by id
+     *
+     * @param  int $id
+     * @return array
+     */
+    public function postId($id)
+    {
+        return $this->get("posts/$id");
+    }
+
     /**
      * Get post by slug
      *