diff --git a/extensions/custis/code/db_schema-abstract_schema.pl b/extensions/custis/code/db_schema-abstract_schema.pl
new file mode 100755
index 000000000..5da65ef53
--- /dev/null
+++ b/extensions/custis/code/db_schema-abstract_schema.pl
@@ -0,0 +1,18 @@
+#!/usr/bin/perl -wT
+
+use strict;
+my $schema = Bugzilla->hook_args->{schema};
+
+# FIELD VALUES FOR INCOMING EMAILS
+# --------------
+
+$schema->{emailin_fields} = {
+    FIELDS => [
+        address => {TYPE => 'varchar(255)', NOTNULL => 1},
+        field   => {TYPE => 'varchar(255)', NOTNULL => 1},
+        value   => {TYPE => 'varchar(255)', NOTNULL => 1},
+    ],
+    INDEXES => [
+        emailin_fields_primary => { FIELDS => ['address', 'field'], TYPE => 'UNIQUE' },
+    ],
+};