app/views/devise/sessions/new.html.erb
<h1 class="centered-overlay__title">Log in</h1>
<%- if devise_mapping.omniauthable? %>
<section class="col-xs-12">
<%= link_to "Sign in with your SumOfUs email", omniauth_authorize_path(resource_name, 'google_oauth2'), class: 'btn btn-primary btn-lg' %><br />
</section>
<% end -%>
<section class="col-xs-12">
<h4>or log in with a password</h4>
<%= form_for(resource, as: resource_name, url: session_path(resource_name)) do |f| %>
<div class="form-group">
<%= f.label :email %><br />
<%= f.email_field :email, class: 'form-control' %>
</div>
<div class="form-group">
<%= f.label :password %><br />
<%= 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="actions form-group">
<%= f.submit "Log in", class: 'btn btn-default' %>
</div>
<% end %>
<div class="form-group">
<%= render "devise/shared/links", no_omniauth: true %>
</div>
</section>