fix: use utc timestamps when determining raw table names

lib/postal/message_db/database.rb

@@ -107,7 +107,7 @@ module Postal
       #
       # Insert a new raw message into a table (creating it if needed)
       #
-      def insert_raw_message(data, date = Date.today)
+      def insert_raw_message(data, date = Time.now.utc.to_date)
         table_name = raw_table_name_for_date(date)
         begin
           headers, body = data.split(/\r?\n\r?\n/, 2)

lib/postal/message_db/message.rb

@@ -263,7 +263,7 @@ module Postal
         return unless @pending_raw_message
 
         self.size = @pending_raw_message.bytesize
-        date = Date.today
+        date = Time.now.utc.to_date
         table_name, headers_id, body_id = @database.insert_raw_message(@pending_raw_message, date)
         self.raw_table = table_name
         self.raw_headers_id = headers_id

lib/postal/message_db/provisioner.rb

@@ -94,7 +94,7 @@ module Postal
       # Return a list of raw message tables that are older than the given date
       #
       def raw_tables(max_age = 30)
-        earliest_date = max_age ? Date.today - max_age : nil
+        earliest_date = max_age ? Time.now.utc.to_date - max_age : nil
         [].tap do |tables|
           @database.query("SHOW TABLES FROM `#{@database.database_name}` LIKE 'raw-%'").each do |tbl|
             tbl_name = tbl.to_a.first.last
@@ -128,7 +128,7 @@ module Postal
       #  Remove messages from the messages table that are too old to retain
       #
       def remove_messages(max_age = 60)
-        time = (Date.today - max_age.days).to_time.end_of_day
+        time = (Time.now.utc.to_date - max_age.days).to_time.end_of_day
         return unless newest_message_to_remove = @database.select(:messages, where: { timestamp: { less_than_or_equal_to: time.to_f } }, limit: 1, order: :id, direction: "DESC", fields: [:id]).first
 
         id = newest_message_to_remove["id"]