Redmine

When viewing an issue detail page, the internal error occurred as follows:

Started GET "/redmine/issues/1" for 127.0.0.1 at 2015-03-04 09:17:21 +0000
Processing by IssuesController#show as HTML
  Parameters: {"id"=>"1"}
  Current user: admin (id=1)
  Rendered issues/_action_menu.html.erb (27.3ms)
  Rendered issues/show.html.erb within layouts/base (66.5ms)
Completed 500 Internal Server Error in 164ms

ActionView::Template::Error (undefined method `project_activity_path' for #<#<Class:0x007f81aca870e8>:0x007f81aca69b10>):
    27: <%= render_issue_subject_with_tree(@issue) %>
    28: </div>
    29:         <p class="author">
    30:         <%= authoring @issue.created_on, @issue.author %>.
    31:         <% if @issue.created_on != @issue.updated_on %>
    32:         <%= l(:label_updated_time, time_tag(@issue.updated_on)).html_safe %>.
    33:         <% end %>
  app/helpers/application_helper.rb:431:in `time_tag'
  app/helpers/application_helper.rb:425:in `authoring'
  app/views/issues/show.html.erb:30:in `_app_views_issues_show_html_erb___2317040810410115667_70097461988680'
  app/controllers/issues_controller.rb:118:in `block (2 levels) in show'
  app/controllers/issues_controller.rb:115:in `show'

Where the project_activity_path method is defined?

My environment information output by ruby bin/about is listed below.

Environment:
  Redmine version                3.0.0.stable.14045
  Ruby version                   2.1.5-p273 (2014-11-13) [x86_64-linux]
  Rails version                  4.2.0
  Environment                    production
  Database adapter               PostgreSQL
SCM:
  Subversion                     1.8.8
  Git                            1.9.1
  Filesystem
Redmine plugins:
  no plugin installed