client.rb

# What we are going to do is retrieve all of the users.
#
# Then loop through all of the users. For each user that
# we loop through, we will get all of their clients.
#
# Then we will loop through each of that user's clients
# and send that client an email.
#
# We will send the client object into daily_email and
# let daily_mail get whatever information it needs
# about the client.
#
def self.daily_email
  @users = User.all
  @users.each do |user|
    clients = user.clients
    clients.each do |client|
      if client.email? && client.reminder == "Daily" && !client.paid?
        puts "Daily fixed | Company Name #{user.username} Client Name | #{client.name}"
        Reminder.test_mail.deliver
        Reminder.daily_email(client).deliver
      end
    end
  end
end

reminder.rb

# This requires that a user has_many :clients
# and a client belongs_to :user.
#
def daily_email(client)
  mail(:to => client.email, :subject => "Reminder from #{client.user.username}" )
  puts "Inside Daily email sent method"
  client.update_attributes(last_email: Time.now, email_sent: true)
end