From https://once.com/writebook

app/controllers/concerns/version_headers.rb

@@ -0,0 +1,13 @@
+module VersionHeaders
+  extend ActiveSupport::Concern
+
+  included do
+    before_action :set_version_headers
+  end
+
+  private
+    def set_version_headers
+      response.headers["X-Version"] = Rails.application.config.app_version
+      response.headers["X-Rev"] = Rails.application.config.git_revision
+    end
+end