Add CheckboxFormField to form field documentation

Close #110

diff --git a/pages/php/api/formBuilder/php_api_form_builder-form_fields.md b/pages/php/api/formBuilder/php_api_form_builder-form_fields.md
index 1071af2819098659fad1b6c0fed0d2bf68cf1bb3..2840d28abd1b4397d2b7203945ce2bffffd0cb6c 100644 (file)
--- a/pages/php/api/formBuilder/php_api_form_builder-form_fields.md
+++ b/pages/php/api/formBuilder/php_api_form_builder-form_fields.md
@@ -38,6 +38,11 @@ Objects of this class require a label.
 The return value of `getSaveValue()` is the integer representation of the boolean value, i.e. `0` or `1`.
 
 
+### <span class="label label-info">5.3.2+</span> `CheckboxFormField`
+
+`CheckboxFormField` extends `BooleanFormField` and offers a simple HTML checkbox.
+
+
 ### `ClassNameFormField`
 
 `ClassNameFormField` is a [text form field](#textformfield) that supports additional settings, specific to entering a PHP class name: