added sieve rule to move spam to junk folder

modoboa_installer/scripts/files/dovecot/conf.d/90-sieve.conf

@@ -38,7 +38,7 @@ plugin {
   # Identical to sieve_before, only the specified scripts are executed after the
   # user's script (only when keep is still in effect!). Multiple script file or
   # directory paths can be specified by appending an increasing number.
-  #sieve_after =
+  {%dovecot_enabled}sieve_after = /etc/dovecot/conf.d/custom_after_sieve
   #sieve_after2 = 
   #sieve_after2 = (etc...)
 

modoboa_installer/scripts/files/dovecot/conf.d/custom_after_sieve/spam-to-junk.sieve.tpl

@@ -0,0 +1,4 @@
+require "fileinto";
+if header :contains "X-Spam-Status" "Yes" {
+    fileinto "Junk";
+}