Merge branch 'patch-26' into 'master'

Delete duplicated lines.

See merge request !14180

app/models/issue.rb

@@ -30,9 +30,6 @@ class Issue < ActiveRecord::Base
   has_many :issue_assignees
   has_many :assignees, class_name: "User", through: :issue_assignees
 
-  has_many :issue_assignees
-  has_many :assignees, class_name: "User", through: :issue_assignees
-
   validates :project, presence: true
 
   scope :in_projects, ->(project_ids) { where(project_id: project_ids) }