wip for db_migrations for core schema

sql/pgsql/migrations/5.sql

@@ -0,0 +1,10 @@
+begin;
+
+create table ttrss_scheduled_updates (id serial not null primary key,
+	owner_uid integer not null references ttrss_users(id) ON DELETE CASCADE,
+	feed_id integer default null references ttrss_feeds(id) ON DELETE CASCADE,
+	entered timestamp not null default NOW());
+
+update ttrss_version set schema_version = 5;
+
+commit;