Fix up db/schema.rb changes leftover and comments out of date

db/schema.rb

@@ -450,7 +450,6 @@ ActiveRecord::Schema.define(version: 20180425131009) do
 
   add_index "ci_runner_groups", ["group_id"], name: "index_ci_runner_groups_on_group_id", using: :btree
   add_index "ci_runner_groups", ["runner_id", "group_id"], name: "index_ci_runner_groups_on_runner_id_and_group_id", unique: true, using: :btree
-  add_index "ci_runner_groups", ["runner_id"], name: "index_ci_runner_groups_on_runner_id", using: :btree
 
   create_table "ci_runner_projects", force: :cascade do |t|
     t.integer "runner_id", null: false
@@ -1573,7 +1572,6 @@ ActiveRecord::Schema.define(version: 20180425131009) do
     t.boolean "merge_requests_rebase_enabled", default: false, null: false
     t.integer "jobs_cache_index"
     t.boolean "pages_https_only", default: true
-    t.boolean "group_runners_enabled", default: true, null: false
   end
 
   add_index "projects", ["ci_id"], name: "index_projects_on_ci_id", using: :btree

lib/gitlab/import_export/import_export.yml

@@ -107,7 +107,6 @@ excluded_attributes:
     - :last_repository_check_at
     - :storage_version
     - :description_html
-    - :group_runners_enabled
   snippets:
     - :expired_at
   merge_request_diff:

spec/factories/projects.rb

@@ -24,8 +24,8 @@ FactoryBot.define do
       merge_requests_access_level ProjectFeature::ENABLED
       repository_access_level ProjectFeature::ENABLED
 
-      # we can't assign the delegated `#settings` attributes directly, as the
-      # `#settings` relation needs to be created first
+      # we can't assign the delegated `#ci_cd_settings` attributes directly, as the
+      # `#ci_cd_settings` relation needs to be created first
       group_runners_enabled nil
     end
 
@@ -52,7 +52,7 @@ FactoryBot.define do
 
       project.group&.refresh_members_authorized_projects
 
-      # assign the delegated `#settings` attributes after create
+      # assign the delegated `#ci_cd_settings` attributes after create
       project.reload.group_runners_enabled = evaluator.group_runners_enabled unless evaluator.group_runners_enabled.nil?
     end