あ、通った
Migrating to IdsToBigints2 (20170924022025)
== 20170924022025 IdsToBigints2: migrating ====================================
-- change_column(:statuses_tags, :tag_id, :bigint)
-> 8.9065s
== 20170924022025 IdsToBigints2: migrated (8.9066s) ===========================