how i can create data binder (directory form binder) plugin

i want to custom dir_user table, and i found little joget app sample for manage user, by default in this sample use directory form binder for load and store data, but i want to more for load and store any field, i try to create plugin it extend to "formBinder" and implement to formLoadBinder,formStoreBinder. but after install this plugin i don't see my plugin in load or store binder(Form Builder properties)

any one to help me. 

Thanks in advance.