undefined method `safety_assured' in Heroku deployment

This is my first deployment of this app to heroku. It failed in one of the migrations. Has anyone seen this? I cloned jumpstart pro just a few days ago. 

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== 20180817230558 DeviseCreateUsers: migrated (0.0330s) =======================

D, [2021-01-17T16:57:42.347667 #4] DEBUG -- :   ActiveRecord::SchemaMigration Create (2.0ms)  INSERT INTO "schema_migrations" ("version") VALUES ($1) RETURNING "version"  [["version", "20180817230558"]]

D, [2021-01-17T16:57:42.351046 #4] DEBUG -- :   TRANSACTION (2.8ms)  COMMIT

I, [2021-01-17T16:57:42.351293 #4]  INFO -- : Migrating to DeviseInvitableAddToUsers (20180820210659)

== 20180820210659 DeviseInvitableAddToUsers: migrating ========================

-- safety_assured()

D, [2021-01-17T16:57:42.377726 #4] DEBUG -- :    (1.6ms)  SELECT pg_advisory_unlock(6626398448378580270)

rails aborted!

StandardError: An error has occurred, this and all later migrations canceled:

undefined method `safety_assured' for #<DeviseInvitableAddToUsers:0x00005599b6786f40>
...

It's my fault. I coomented out the strong_migrations gem