HasOnePickerField - link existing

[djmattski]

If you are using the SS4 forked version (https://github.com/thewebmen/silverstripe-pickerfield) - I have noticed that using the HasOnePickerField to link existing relations does not work if you follow the documentation.

PickerFieldAddExistingSearchHandler.php Line: 26 appends 'ID' to the field name - where the documentation asks you to add in the field name + ID in the constructor. So you end up with fieldnameIDID which does not work.

So construct it as so rather:
HasOnePickerField::create($this, 'Thing', 'Thing', $this->Thing());