Fix coding standards

.rubocop.yml

@@ -35,7 +35,7 @@ Rails/SkipsModelValidations:
 Rails/CreateTableWithTimestamps:
   Enabled: false
 
-# we drop this, if we drop Rails 4.2 support
+# app/model/application_record.rb is missing in redmine, we can't use ApplicationRecord
 Rails/ApplicationRecord:
   Enabled: false
 

app/helpers/additionals_tag_helper.rb

@@ -102,7 +102,7 @@ module AdditionalsTagHelper
   end
 
   def additionals_tag_color(tag_name)
-    "##{'%06x' % (tag_name.unpack('H*').first.hex % 0xffffff)}"
+    "##{format('%06x', tag_name.unpack('H*').first.hex % 0xffffff)}"
   end
 
   def cloudify(tags)

lib/additionals.rb

@@ -2,7 +2,7 @@ module Additionals
   MAX_CUSTOM_MENU_ITEMS = 5
   SELECT2_INIT_ENTRIES = 20
 
-  LIST_SEPARATOR = ' » '.html_safe # rubocop:disable Rails/OutputSafety
+  LIST_SEPARATOR = ' » '.html_safe
 
   class << self
     def setup