refs #124: add redirect to valid conference home for crew members

app/controllers/home_controller.rb

@@ -8,6 +8,11 @@ def index
       return redirect_to new_conference_path
     end
     if cannot? :read, Conference
+      # maybe a crew user tries to login to the wrong conference?
+      if current_user.is_crew?
+        conference = current_user.conference_users.map { |cu| cu.conference }.last
+        return redirect_to conference_home_path(conference_acronym: conference.acronym) if conference.present?
+      end
       return redirect_to cfp_root_path
     end
     @versions = Version.where(conference_id: @conference.id).includes(:item).order("created_at DESC").limit(5)