Add upgrade guide.

Author: yajra

buttons-extended.md

@@ -2,6 +2,36 @@
 
 We can now extend and reuse our DataTable class inside our controller by using `before` and `response` callback.
 
+> IMPORTANT: Extended DataTable is only applicable on `^1.1` and above.
+
+
+## Upgrading from v1.0 to v1.1
+- Upgrade to `laravel-datatables-buttons:^1.1`
+- Rename `ajax()` method to `dataTable()`
+- Remove `->make(true)` from the method chain.
+
+```php
+    public function ajax()
+    {
+        return $this->datatables
+            ->eloquent($this->query())
+            ->addColumn('action', 'path.to.action.view')
+            ->make(true)
+    }
+```
+
+TO
+
+
+```php
+    public function dataTable()
+    {
+        return $this->datatables
+            ->eloquent($this->query())
+            ->addColumn('action', 'path.to.action.view');
+    }
+```
+
 ## Quick Example:
 ```php
 Route::get('datatable', function(RolesDataTable $dataTable){
@@ -14,4 +44,3 @@ Route::get('datatable', function(RolesDataTable $dataTable){
    })->render('path.to.view');
 });
 ```
-