style(rubocop): Naming/MemoizedInstanceVariableName

lib/postal/query_string.rb

@@ -8,12 +8,12 @@ module Postal
     end
 
     def [](value)
-      to_hash[value.to_s]
+      hash[value.to_s]
     end
 
-    delegate :empty?, to: :to_hash
+    delegate :empty?, to: :hash
 
-    def to_hash
+    def hash
       @hash ||= @string.scan(/([a-z]+):\s*(?:(\d{2,4}-\d{2}-\d{2}\s\d{2}:\d{2})|"(.*?)"|(.*?))(\s|\z)/).each_with_object({}) do |(key, date, string_with_spaces, value), hash|
         if date
           actual_value = date

lib/postal/worker.rb

@@ -202,7 +202,7 @@ module Postal
       end
 
       def job_channel
-        @channel ||= Postal::RabbitMQ.create_channel
+        @job_channel ||= Postal::RabbitMQ.create_channel
       end
 
       def job_queue(name)