allow to synchronize all articles of a shared supplier

app/views/suppliers/_form.html.haml

@@ -16,6 +16,8 @@
   = f.input :order_howto, as: :text, input_html: {rows: 5}
   = f.input :note, as: :text, input_html: {rows: 5}
   = f.input :min_order_quantity
+  - if @supplier.shared_supplier
+    = f.input :shared_sync_method, collection: shared_sync_method_collection(@supplier.shared_supplier), input_html: {class: 'input-xlarge'}, include_blank: false, disabled: @supplier.shared_supplier.shared_sync_methods.count < 2
   .form-actions
     = f.submit class: 'btn'
     = link_to t('ui.or_cancel'), suppliers_path

app/views/suppliers/show.html.haml

@@ -10,6 +10,7 @@
     - if shared_supplier = @supplier.shared_supplier
       .alert.alert-info
         = t 'suppliers.shared_supplier_note'
+        = t "suppliers.shared_supplier_methods.#{@supplier.shared_sync_method}"
 
     %dl.dl-horizontal
       %dt= heading_helper(Supplier, :address) + ':'