Sprinkle frozen string literal & Indentation Fix (#150)

* Avoid extra string alocation as join will always return string

* Fix indentation

* Sprinkle frozen string literal true

lib/integrations/facebook/delivery_status.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 class Integrations::Facebook::DeliveryStatus
 
   def initialize(params)

lib/integrations/facebook/message_creator.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 class Integrations::Facebook::MessageCreator
 
   attr_reader :response
@@ -28,8 +30,8 @@ class Integrations::Facebook::MessageCreator
 
   def create_outgoing_message
     FacebookPage.where(page_id: response.sender_id).each do |page|
-        mb = Messages::Outgoing::EchoBuilder.new(response, page.inbox, true)
-        mb.perform
+      mb = Messages::Outgoing::EchoBuilder.new(response, page.inbox, true)
+      mb.perform
     end
   end
 

lib/integrations/facebook/message_parser.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 class Integrations::Facebook::MessageParser
 
   def initialize(response_json)