Error 500 Creating Wiki Page (Gitlab CE 8.7.0 )

When I attempt to create a wiki page under a project and hit the "create page" button i get an error 500. When looking at the logs this is what I see

Processing by Projects::WikisController#create as HTML Parameters: {"utf8"=>"✓", "authenticity_token"=>"[FILTERED]", "wiki"=>{"title"=>"home", "format"=>"markdown", "content"=>"#Table of Contents", "message"=>""}, "namespace_id"=>"tech", "project_id"=>"dev"} Completed 500 Internal Server Error in 36ms (ActiveRecord: 3.2ms)

NoMethodError (undefined method username' for #<Group:0x00000007a2c928>): 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'