Gitlab ce 8.7.0 bug in wiki POST /groupname/projectname/wikis, updating to 8.7.3 fixes

I’m getting an error 500 message due to what appears to be a missing method in some ruby code in the post-handler for creating a wiki inside one of my projects. Seems to be a bug in app/models/project_wiki.rb in GitLab Community Edition 8.7.0 f2a3f70

Screenshot shows me clicking create:

Here is the information from gitlab-ctl tail:

json HTTP/1.1" 404 27 "-" "Go 1.1 package http"

==> /var/log/gitlab/gitlab-rails/production.log <==
Started POST "/powerserver7/RamSoft.WorklistPrototype2/wikis" for at 2016-05-06 08:15:12 -0500
Processing by Projects::WikisController#create as HTML
  Parameters: {"utf8"=>"✓", "authenticity_token"=>"[FILTERED]", "wiki"=>{"title"=>"home", "format"=>"markdown", "content"=>"Test", "message"=>"Test wiki edit"}, "namespace_id"=>"powerserver7", "project_id"=>"RamSoft.WorklistPrototype2"}
Completed 500 Internal Server Error in 96ms (ActiveRecord: 7.3ms)

NoMethodError (undefined method `username' for #<Group:0x00000009313090>):
  app/models/project_wiki.rb:158:in `default_message'
  app/models/project_wiki.rb:152:in `commit_details'
  app/models/project_wiki.rb:91:in `create_page'
  app/models/wiki_page.rb:183:in `save'
  app/models/wiki_page.rb:143:in `create'
  app/services/wiki_pages/create_service.rb:6:in `execute'
  app/controllers/projects/wikis_controller.rb:58:in `create'
  lib/gitlab/middleware/go.rb:16:in `call'

==> /var/log/gitlab/gitlab-workhorse/current <==
2016-05-06_13:15:12.19302 2016/05/06 08:15:12 ErrorPage: serving predefined error page: 500

Posting this here in case it helps. It no longer reproduces in 8.7.3.