Just a table of current members, sorted by email address (or via some JavaScript plugin, make it sortable, etc.) Buttons for edit/delete for each row like ActiveAdmin. Button for add. Pretty much everything should be standard RESTful stuff:
Edit goes to GET /memberships/_membershipid/edit
Delete goes to DELETE /memberships/_membershipid then redirects here
Add goes to GET /memberships/new?organization_id=org
Route: GET /memberships/index?organization_id=org
Just a table of current members, sorted by email address (or via some JavaScript plugin, make it sortable, etc.) Buttons for edit/delete for each row like ActiveAdmin. Button for add. Pretty much everything should be standard RESTful stuff: