500 on project home/settings/issue details/..

Summary

We are running a self-hosted omnibus Gitlab, updated this morning to 10.1. Since then we cant browse any project home or settings or issue details. No problem in the other sections (issues, repo, snippets, ...)

Steps to reproduce

• Browse to any project home (e.g. https:/your-gitlab/group1/project1) or settings (e.g. https:/your-gitlab/group1/project1/edit) or issue details (e.g. https:/your-gitlab/group1/project1/issues/1).
• Get a 500 error

Relevant logs and/or screenshots

tarted GET "/group1/project1" for 151.65.116.107 at 2017-10-23 10:37:56 +0200
Started GET "/-/metrics" for 127.0.0.1 at 2017-10-23 10:37:57 +0200
Processing by MetricsController#index as HTML
Filter chain halted as :validate_prometheus_metrics rendered or redirected
Completed 404 Not Found in 45ms (Views: 44.3ms | ActiveRecord: 0.0ms)
Processing by ProjectsController#show as HTML
Parameters: {"namespace_id"=>"group1", "id"=>"project1"}
Completed 500 Internal Server Error in 136ms (ActiveRecord: 9.5ms)
ActiveRecord::StatementInvalid (PG::UndefinedTable: ERROR: relation "fork_network_members" does not exist
LINE 5: WHERE a.attrelid = '"fork_network_members"'::...
^
: SELECT a.attname, format_type(a.atttypid, a.atttypmod),
pg_get_expr(d.adbin, d.adrelid), a.attnotnull, a.atttypid, a.atttypmod
FROM pg_attribute a LEFT JOIN pg_attrdef d
ON a.attrelid = d.adrelid AND a.attnum = d.adnum
WHERE a.attrelid = '"fork_network_members"'::regclass
AND a.attnum > 0 AND NOT a.attisdropped
ORDER BY a.attnum
):
app/models/project.rb:1012:in `forked?'
app/models/project.rb:634:in `import?'
app/models/project.rb:654:in `import_started?'
app/models/project.rb:650:in `import_in_progress?'
app/controllers/projects_controller.rb:102:in `show'
lib/gitlab/i18n.rb:47:in `with_locale'
lib/gitlab/i18n.rb:53:in `with_user_locale'
app/controllers/application_controller.rb:337:in `set_locale'
lib/gitlab/middleware/multipart.rb:93:in `call'
lib/gitlab/request_profiler/middleware.rb:14:in `call'
lib/gitlab/middleware/go.rb:17:in `call'
lib/gitlab/etag_caching/middleware.rb:11:in `call'
lib/gitlab/middleware/read_only.rb:30:in `call'
lib/gitlab/request_context.rb:18:in `call'
lib/gitlab/metrics/requests_rack_middleware.rb:27:in `call'