Update README.md

Update examples for #155

README.md

@@ -113,6 +113,7 @@ print_r($csv->data_types);
 
 **Modify data in a CSV file**
 
+Change data values:
 ```php
 $csv = new ParseCsv\Csv();
 $csv->sort_by = 'id';
@@ -122,6 +123,14 @@ $csv->data[4] = array('firstname' => 'John', 'lastname' => 'Doe', 'email' => 'jo
 $csv->save();
 ```
 
+Enclose each data value by quotes:
+```php
+$csv = new ParseCsv\Csv();
+$csv->parse('data.csv');
+$csv->enclose_all = true;
+$csv->save();
+```
+
 **Replace field names or set ones if missing**
 
 ```php