Implement a second round of review comments from @DouweM.

- Don't use `TableReferences` - using `.arel_table` is shorter!
- Move some database-related code to `Gitlab::Database`
- Remove the `MergeRequest#issues_closed` and
  `Issue#closed_by_merge_requests`  associations. They were either
  shadowing or were too similar to existing methods. They are not being
  used anywhere, so it's better to remove them to reduce confusion.
- Use Rails 3-style validations
- Index for `MergeRequest::Metrics#first_deployed_to_production_at`
- Only include `CycleAnalyticsHelpers::TestGeneration` for specs that
  need it.
- Other minor refactorings.

1 files changed, 2 insertions, 1 deletions

diff --git a/app/models/issue.rb b/app/models/issue.rb
index 6a264ace165..25ba38a1cff 100644
--- a/app/models/issue.rb
+++ b/app/models/issue.rb
@@ -24,7 +24,6 @@ class Issue < ActiveRecord::Base
   has_many :events, as: :target, dependent: :destroy
 
   has_many :merge_requests_closing_issues, class_name: 'MergeRequestsClosingIssues'
-  has_many :closed_by_merge_requests, through: :merge_requests_closing_issues, source: :merge_request
 
   validates :project, presence: true
 
@@ -39,6 +38,8 @@ class Issue < ActiveRecord::Base
   scope :order_due_date_asc, -> { reorder('issues.due_date IS NULL, issues.due_date ASC') }
   scope :order_due_date_desc, -> { reorder('issues.due_date IS NULL, issues.due_date DESC') }
 
+  scope :created_after, -> (datetime) { where("created_at >= ?", datetime) }
+
   attr_spammable :title, spam_title: true
   attr_spammable :description, spam_description: true