Error 500 on Start Screen in GitLab 8.6rc2 using Omnibus Package and external Postgres

I'm using external postgres. when installing rc2 over gitlab 8.5.7 the installer crashed saying pg_trgm extension is not installed. I installed for gitlabhq_production and run package installation again.

now gitlab is back running but accessing the start page is giving error 500. heres the relevant log entries.

Completed 500 Internal Server Error in 1324ms (ActiveRecord: 303.9ms)

ActionView::Template::Error (undefined method `main_language' for #<Project:0x0000000617d508>):

28: = project.name

29:

30: .controls

31: - if project.main_language

32: %span

33: = project.main_language

34: - if ci_commit

app/views/shared/projects/_project.html.haml:31:in `block in _app_views_shared_projects__project_html_haml___4594022469146111637_51784420'

app/views/shared/projects/_project.html.haml:14:in `_app_views_shared_projects__project_html_haml___4594022469146111637_51784420'

app/views/shared/projects/_list.html.haml:16:in `block in _app_views_shared_projects__list_html_haml__1785397051136208547_50931000'

app/views/shared/projects/_list.html.haml:14:in `_app_views_shared_projects__list_html_haml__1785397051136208547_50931000'

app/views/dashboard/projects/_projects.html.haml:1:in `_app_views_dashboard_projects__projects_html_haml__1430865416751087473_50895380'

app/views/dashboard/projects/index.html.haml:14:in `_app_views_dashboard_projects_index_html_haml__3637439534008868330_50054700'

app/controllers/dashboard/projects_controller.rb:15:in `index'

app/controllers/root_controller.rb:13:in `index'

lib/gitlab/middleware/go.rb:16:in `call'

Started GET "/" for 80.187.110.7:18511 at 2016-03-17 07:43:24 +0100