DEV: Migrate Github authentication to ManagedAuthenticator (#11170)

This commit adds an additional find_user_by_email hook to ManagedAuthenticator so that GitHub login can continue to support secondary email addresses

The github_user_infos table will be dropped in a follow-up commit.

This is the last core authenticator to be migrated to ManagedAuthenticator 🎉

app/models/github_user_info.rb

@@ -1,22 +0,0 @@
-# frozen_string_literal: true
-
-class GithubUserInfo < ActiveRecord::Base
-  belongs_to :user
-end
-
-# == Schema Information
-#
-# Table name: github_user_infos
-#
-#  id             :integer          not null, primary key
-#  user_id        :integer          not null
-#  screen_name    :string           not null
-#  github_user_id :integer          not null
-#  created_at     :datetime         not null
-#  updated_at     :datetime         not null
-#
-# Indexes
-#
-#  index_github_user_infos_on_github_user_id  (github_user_id) UNIQUE
-#  index_github_user_infos_on_user_id         (user_id) UNIQUE
-#

app/models/user.rb

@@ -40,7 +40,6 @@ class User < ActiveRecord::Base
 
   has_one :user_option, dependent: :destroy
   has_one :user_avatar, dependent: :destroy
-  has_one :github_user_info, dependent: :destroy
   has_one :primary_email, -> { where(primary: true)  }, class_name: 'UserEmail', dependent: :destroy
   has_one :user_stat, dependent: :destroy
   has_one :user_profile, dependent: :destroy, inverse_of: :user

app/services/user_anonymizer.rb

@@ -60,7 +60,6 @@ class UserAnonymizer
       end
 
       @user.user_avatar.try(:destroy)
-      @user.github_user_info.try(:destroy)
       @user.single_sign_on_record.try(:destroy)
       @user.oauth2_user_infos.try(:destroy_all)
       @user.user_associated_accounts.try(:destroy_all)