Migrate runners token first before fully switching

app/models/ci/runner.rb

@@ -10,7 +10,7 @@ module Ci
     include FromUnion
     include TokenAuthenticatable
 
-    add_authentication_token_field :token, encrypted: true, fallback: true
+    add_authentication_token_field :token, encrypted: true, migrating: true
 
     enum access_level: {
       not_protected: 0,

app/models/group.rb

@@ -55,7 +55,7 @@ class Group < Namespace
 
   validates :two_factor_grace_period, presence: true, numericality: { greater_than_or_equal_to: 0 }
 
-  add_authentication_token_field :runners_token, encrypted: true, fallback: true
+  add_authentication_token_field :runners_token, encrypted: true, migrating: true
 
   after_create :post_create_hook
   after_destroy :post_destroy_hook

app/models/project.rb

@@ -85,7 +85,7 @@ class Project < ActiveRecord::Base
   default_value_for :snippets_enabled, gitlab_config_features.snippets
   default_value_for :only_allow_merge_if_all_discussions_are_resolved, false
 
-  add_authentication_token_field :runners_token, encrypted: true, fallback: true
+  add_authentication_token_field :runners_token, encrypted: true, migrating: true
 
   before_validation :mark_remote_mirrors_for_removal, if: -> { RemoteMirror.table_exists? }