Rummage Portal field has wrong field type

[joemull]

Problem

When I want to filter supporters by country, the filter is not applied.

This is because the widget provides multiple choices, but the form field is a single choice field:

janeway/src/core/forms/forms.py

Lines 698 to 702 in 3cad511

	self.fields[facet_key] = forms.ChoiceField(
	widget=forms.widgets.CheckboxSelectMultiple,
	choices=choices,
	required=False,
	)

As a result the data is misaligned when the form is validated.

Proposed solution

Use MultipleChoiceField.