panel/app/views/posts/_form.haml

- unless @post.errors.empty?
  .alert.alert-danger
    %ul
      - @post.errors.each do |error|
        %li= error

= form_tag site_post_path(@site, @post), method: :patch, class: 'form' do
  .form-group
    = submit_tag t('posts.save'), class: 'btn btn-success'
  .form-group
    = text_field 'post', 'title', value: @post.title, class: 'form-control',
      placeholder: t('posts.title')
  .form-group
    = text_area_tag 'post[content]', @post.content, autofocus: true,
      class: 'form-control post-content', data: { provide: 'markdown' }
  .form-group
    = label_tag 'post_date', t('posts.date')
    = date_field 'post', 'date', value: @post.date.strftime('%F'),
      class: 'form-control'
    %small.text-muted.form-text= t('posts.date_help')
  .form-group
    = label_tag 'post_categories', t('posts.categories')
    = text_field 'post', 'categories', value: @post.categories.join(', '),
      class: 'form-control'
    %small.text-muted.form-text= t('posts.tags_help')
  .form-group
    = label_tag 'post_tags', t('posts.tags')
    = text_field 'post', 'tags', value: @post.tags.join(', '),
      class: 'form-control'
    %small.text-muted.form-text= t('posts.tags_help')
  .form-group
    = label_tag 'post_slug', t('posts.slug')
    = text_field 'post', 'slug', value: @post.slug,
      class: 'form-control'
    %small.text-muted.form-text= t('posts.slug_help')