diff --git a/lib/ridgepole/diff.rb b/lib/ridgepole/diff.rb
index <HASH>..<HASH> 100644
--- a/lib/ridgepole/diff.rb
+++ b/lib/ridgepole/diff.rb
@@ -1,5 +1,5 @@
 class Ridgepole::Diff
-  PRIMARY_KEY_OPTIONS = %i(id limit default null precision scale collation unsigned comment).freeze
+  PRIMARY_KEY_OPTIONS = %i(id limit default null precision scale collation unsigned).freeze
 
   def initialize(options = {})
     @options = options
fix: don't treat the `comment` option as a option of primary key

ActiveRecord 5 allows to specify the `comment` option on
`create_table`, but this option adds the comment for tables
not a primary key.