allow user input for csv options

ActiveAdmin.register Post  do
        active_admin_import validate: false,
                          template: 'import' ,
                          template_object: ActiveAdminImport::Model.new(
                              hint: "you can configure CSV options",
                              csv_options: { col_sep: ";", row_sep: nil, quote_char: nil }
                          )
end                      

override template app/views/import.html.erb

 <p>
       <%= raw(@active_admin_import_model.hint) %> 
    </p>
    <%= semantic_form_for @active_admin_import_model, url: {action: :do_import}, html: {multipart: true} do |f| %>
        <%= f.inputs do %>
            <%= f.input :file, as: :file %>
        <% end %>
        <%= f.inputs "CSV options", for: [:csv_options, OpenStruct.new(@active_admin_import_model.csv_options)] do |csv| %>
            <% csv.with_options input_html: {style: 'width:40px;'} do |opts| %>
                <%= opts.input :col_sep %>
                <%= opts.input :row_sep %>
                <%= opts.input :quote_char %>
            <% end %>
        <% end %>

        <%= f.actions do %>
            <%= f.action :submit, label: t("active_admin_import.import_btn"), button_html: {disable_with: t("active_admin_import.import_btn_disabled")} %>
        <% end %>
    <% end %>