Added relationships between Release and Milestone

Modified schema via migrations.
Added one-to-one relationship between the two models.
Added changelog file

1 files changed, 17 insertions, 0 deletions

diff --git a/app/models/milestone_release.rb b/app/models/milestone_release.rb
new file mode 100644
index 00000000000..c8743a8cad8
--- /dev/null
+++ b/app/models/milestone_release.rb
@@ -0,0 +1,17 @@
+# frozen_string_literal: true
+
+class MilestoneRelease < ApplicationRecord
+  belongs_to :milestone
+  belongs_to :release
+
+  validates :milestone_id, uniqueness: { scope: [:release_id] }
+  validate :same_project_between_milestone_and_release
+
+  private
+
+  def same_project_between_milestone_and_release
+    return if milestone&.project_id == release&.project_id
+
+    errors.add(:base, 'does not have the same project as the milestone')
+  end
+end