style(rubocop): fix all safe auto correctable offenses

app/models/concerns/has_message.rb

@@ -5,7 +5,7 @@ module HasMessage
   end
 
   def message
-    @message ||= self.server.message_db.message(self.message_id)
+    @message ||= server.message_db.message(message_id)
   end
 
   def message=(message)
@@ -14,6 +14,7 @@ module HasMessage
   end
 
   module ClassMethods
+
     def include_message
       queued_messages = all.to_a
       server_ids = queued_messages.map(&:server_id).uniq
@@ -22,10 +23,11 @@ module HasMessage
       elsif server_ids.size > 1
         raise Postal::Error, "'include_message' can only be used on collections of messages from the same server"
       end
+
       message_ids = queued_messages.map(&:message_id).uniq
       server = queued_messages.first&.server
-      messages = server.message_db.messages(:where => {:id => message_ids}).each_with_object({}) do |message, hash|
-        hash[message.id] = message
+      messages = server.message_db.messages(where: { id: message_ids }).index_by do |message|
+        message.id
       end
       queued_messages.each do |queued_message|
         if m = messages[queued_message.message_id]
@@ -33,6 +35,7 @@ module HasMessage
         end
       end
     end
+
   end
 
 end