app/views/devise/sessions/new.html.erb
<div class="row justify-content-xl-center">
<div class="col-xl-4">
<h2><%= t('devise.sessions.login') %></h2>
<%= form_for(resource, as: resource_name, url: session_path(resource_name), class: 'form-horizontal') do |f| %>
<div class="form-group">
<%= f.label :email %>
<%= f.email_field :email, autofocus: true, class: 'form-control' %>
</div>
<div class="form-group">
<%= f.label :password %>
<%= f.password_field :password, autocomplete: 'off', class: 'form-control' %>
</div>
<% if devise_mapping.rememberable? -%>
<div class="form-group">
<%= f.check_box :remember_me %>
<%= f.label :remember_me %>
</div>
<% end -%>
<div class="form-group">
<%= f.submit t('devise.sessions.login'), class: 'btn btn-primary' %>
</div>
<div class="form-group">
<%= link_to user_github_omniauth_authorize_path, method: :post do %>
<i class="fab fa-github fa-2x"></i>
<% end %>
<%= link_to user_facebook_omniauth_authorize_path, method: :post do %>
<i class="fab fa-facebook-square fa-2x"></i>
<% end %>
<%= link_to user_twitter_omniauth_authorize_path, method: :post do %>
<i class="fab fa-twitter-square fa-2x"></i>
<% end %>
</div>
<% end %>
<div class="shared form-group">
<%= render 'devise/shared/links' %>
</div>
</div>
</div>