feat(login page): hide the Facebook button

Author: andreybakanovsky

app/views/devise/sessions/new.html.slim

@@ -12,7 +12,7 @@
                   figure.image.is-24x24
                     = image_tag('google.svg', class:'is-rounded',  alt: 'G')
                 |   Google
-              = link_to "#", method: :post, class: 'button has-fixed-width is-outlined is-budgeting-kid-hoverable' do
+              /= link_to "#", method: :post, class: 'button has-fixed-width is-outlined is-budgeting-kid-hoverable' do
                 span
                   figure.image.is-24x24
                     = image_tag('facebook.svg', class:'is-rounded',  alt: 'G')