user.rb

class User
  def follow_default_users
    default_user_emails = ['vulume@vulume.com']
    
    default_user_emails.each do |email|
      follow_with_email!(email)
    end
  end
  
  def follow_with_email!(email)
    user = User.find_by_email(email)
    follow!(user) if user
  end
end

Usage:

user = # persisted User model
user.follow_default_users
user.do_something_else