Move ref slug helper to HasRef module

app/models/ci/bridge.rb

@@ -5,6 +5,7 @@ module Ci
     include Ci::Processable
     include Importable
     include AfterCommitQueue
+    include HasRef
     include Gitlab::Utils::StrongMemoize
 
     belongs_to :project

app/models/ci/build.rb

@@ -398,17 +398,6 @@ module Ci
       options&.dig(:environment, :on_stop)
     end
 
-    # A slugified version of the build ref, suitable for inclusion in URLs and
-    # domain names. Rules:
-    #
-    #   * Lowercased
-    #   * Anything not matching [a-z0-9-] is replaced with a -
-    #   * Maximum length is 63 bytes
-    #   * First/Last Character is not a hyphen
-    def ref_slug
-      Gitlab::Utils.slugify(ref.to_s)
-    end
-
     ##
     # Variables in the environment name scope.
     #

app/models/concerns/has_ref.rb

@@ -14,4 +14,15 @@ module HasRef
       Gitlab::Git::TAG_REF_PREFIX + ref.to_s
     end
   end
+
+  # A slugified version of the build ref, suitable for inclusion in URLs and
+  # domain names. Rules:
+  #
+  #   * Lowercased
+  #   * Anything not matching [a-z0-9-] is replaced with a -
+  #   * Maximum length is 63 bytes
+  #   * First/Last Character is not a hyphen
+  def ref_slug
+    Gitlab::Utils.slugify(ref.to_s)
+  end
 end