users: fix incorrect count columns on users table.

Fix incorrect post_upload_count, note_update_count, and
unread_dmail_count columns on the users table.

script/fixes/base.rb

@@ -0,0 +1,11 @@
+require_relative "../../config/environment"
+
+# Run a block of code in a transaction, and only commit it after confirmation.
+def with_confirmation(&block)
+  ApplicationRecord.transaction do
+    yield
+
+    print "Commit? (yes/no): "
+    raise "abort" unless STDIN.readline.chomp == "yes"
+  end
+end