FIX: ensure more secrecy in the gift exchange

FIX: ensure more secrecy in the gift exchange

As @eviltrout cleverly suggested, maleficent admins might be able to identify the matches by looking at the timestamps of the (encrypted) topics that were created by the system user.

Shuffling the pairs should be enough to prevent any fun from being ruined.

diff --git a/jobs/scheduled/gift_exchange.rb b/jobs/scheduled/gift_exchange.rb
index 4fbacea..3efc671 100644
--- a/jobs/scheduled/gift_exchange.rb
+++ b/jobs/scheduled/gift_exchange.rb
@@ -23,8 +23,11 @@ module Jobs
 
       usernames.shuffle!
       usernames << usernames[0]
+      
+      # shuffle the pairs to prevent prying eyes to identify matches by looking at the timestamps of the topics
+      pairs = usernames.each_cons(2).to_a.shuffle
 
-      usernames.each_cons(2).each do |gifter, giftee|
+      pairs.each do |gifter, giftee|
         raw = <<~MD
         Thanks for signing up for the **#{now.year} Discourse Holiday Secret Gift Exchange**!

GitHub sha: b128c82a