Only send planting reminders to confirmed accounts

lib/tasks/growstuff.rake

@@ -48,7 +48,7 @@ namespace :growstuff do
     every_n_weeks = 2 # send fortnightly
 
     if Date.today.cwday == send_on_day and Date.today.cw_week % every_n_weeks == 0
-      Member.find_each do |m|
+      Member.confirmed.find_each do |m|
         Notifier.planting_reminder(m).deliver!
       end
     end