Ruby Code Below,
<%= form_for :article, :html => { :class => "article-form" } do |form| %>
<p>
<%= form.label :title %>
<%=
form.text_field :title,
placeholder: "A******'s title"
%>
</p>
<p>
<%= form.label :text %>
<%=
form.text_field :text,
placeholder: "A******'s content"
%>
</p>
<p>
<%= form.submit %>
</p>
<% end %>
HTML-вывод ниже,
<form class="article-form" action="/articles/new" accept-charset="UTF-8" method="post"><input name="utf8" type="hidden" value="✓"><input type="hidden" name="authenticity_token" value="BRBjb0maKb5kNbGXV0wwoLeFUV6El2la/sOwweWhyN+nEIOK2Wam5Xz8PasZtpwvmiCF7yIO8Pab/OR2uoeZQA==">
<p>
<label for="article_title">Title</label>
<input placeholder="A******'s title" type="text" name="article[title]" id="article_title">
</p>
<p>
<label for="article_text">Text</label>
<input placeholder="A******'s content" type="text" name="article[text]" id="article_text">
</p>
<p>
<input type="submit" name="commit" value="Save Article">
</p>
</form>