Make sign up links like buttons

app/views/devise/_links.erb

@@ -1,21 +1,31 @@
 <%- if controller_name != 'sessions' %>
-  <%= link_to "Sign in", new_session_path(resource_name) %><br />
+  <p>
+  <%= link_to "Sign in", new_session_path(resource_name), class: "btn btn-block" %><br />
+  </p>
 <% end -%>
 
 <%- if devise_mapping.registerable? && controller_name != 'registrations' %>
-  <%= link_to "Sign up", new_registration_path(resource_name) %><br />
+  <p>
+  <%= link_to "Sign up", new_registration_path(resource_name), class: "btn btn-block" %><br />
+  </p>
 <% end -%>
 
 <%- if devise_mapping.recoverable? && controller_name != 'passwords' %>
-  <%= link_to "Forgot your password?", new_password_path(resource_name) %><br />
+  <p>
+  <%= link_to "Forgot your password?", new_password_path(resource_name), class: "btn btn-block" %><br />
+  </p>
 <% end -%>
 
 <%- if devise_mapping.confirmable? && controller_name != 'confirmations' %>
-  <%= link_to "Didn't receive confirmation instructions?", new_confirmation_path(resource_name) %><br />
+  <p>
+  <%= link_to "Didn't receive confirmation instructions?", new_confirmation_path(resource_name), class: "btn btn-block" %><br />
+  </p>
 <% end -%>
 
 <%- if devise_mapping.lockable? && resource_class.unlock_strategy_enabled?(:email) && controller_name != 'unlocks' %>
-  <%= link_to "Didn't receive unlock instructions?", new_unlock_path(resource_name) %><br />
+  <p>
+  <%= link_to "Didn't receive unlock instructions?", new_unlock_path(resource_name), class: "btn btn-block" %><br />
+  </p>
 <% end -%>
 
 <%- if devise_mapping.omniauthable? %>