Log newsletter emails sent

With this commit we are logging which emails have already received the
newsletter

This could be important if something goes wrong sending the newsletter,
to be able to identify which users have already received the newsletter
and be able to skip them

We’ve had to add a new action to the Activity model (email) and add
paranoia features to be able to deal gracefully with the default
`with_hidden` scope in Activities[1]

[1]
https://github.com/AyuntamientoMadrid/consul/blob/master/app/models/acti
vity.rb#L2

app/models/activity.rb

@@ -2,7 +2,7 @@ class Activity < ActiveRecord::Base
   belongs_to :actionable, -> { with_hidden }, polymorphic: true
   belongs_to :user, -> { with_hidden }
 
-  VALID_ACTIONS = %w(hide block restore valuate)
+  VALID_ACTIONS = %w(hide block restore valuate email)
 
   validates :action, inclusion: {in: VALID_ACTIONS}
 

app/models/newsletter.rb

@@ -8,6 +8,9 @@ class Newsletter < ActiveRecord::Base
 
   validates_format_of :from, :with => /@/
 
+  acts_as_paranoid column: :hidden_at
+  include ActsAsParanoidAliases
+
   def list_of_recipient_emails
     UserSegments.user_segment_emails(segment_recipient) if valid_segment_recipient?
   end
@@ -24,8 +27,9 @@ class Newsletter < ActiveRecord::Base
     run_at = first_batch_run_at
     list_of_recipient_emails_in_batches.each do |recipient_emails|
       recipient_emails.each do |recipient_email|
-        Mailer.delay(run_at: run_at).newsletter(self, recipient_email)
         if valid_email?(recipient_email)
+          Mailer.delay(run_at: run_at).newsletter(self, recipient_email)
+          log_delivery(recipient_email)
         end
       end
       run_at += batch_interval
@@ -57,4 +61,9 @@ class Newsletter < ActiveRecord::Base
   def valid_email?(email)
     email.match(/\A([^@\s]+)@((?:[-a-z0-9]+\.)+[a-z]{2,})\Z/i)
   end
+
+  def log_delivery(recipient_email)
+    user = User.where(email: recipient_email).first
+    Activity.log(user, :email, self)
+  end
 end