Update secrets based on the previous release

We were copying the current SMTP and SSL settings to the secrets file
after overwriting them, but we need to copy them before overwriting
them.

The workaround I've found is to copy the tasks to the folder of the
previous release and execute them there.

config/deploy.rb

@@ -133,9 +133,19 @@ end
 
 task :smtp_and_ssl_secrets do
   on roles(:app) do
-    within release_path do
+    within current_path do
       with rails_env: fetch(:rails_env) do
+        tasks_file_path = "lib/tasks/secrets.rake"
+
+        unless test("[ -e #{current_path}/#{tasks_file_path} ]")
+          begin
+            execute "cp #{release_path}/#{tasks_file_path} #{current_path}/#{tasks_file_path}"
+
             execute :rake, "secrets:smtp_and_ssl"
+          ensure
+            execute "rm #{current_path}/#{tasks_file_path}"
+          end
+        end
       end
     end
   end