pgsql support

I can not create patches, so I am putting this here;

    case 'pgsql':
      db_query('CREATE TABLE {job_queue} (
        jqid serial,
        created int NOT NULL,
        description varchar(255) NOT NULL,
        function varchar(255) NOT NULL,
        arguments text NOT NULL,
        file varchar(255) NOT NULL,
        priority smallint NOT NULL,
        PRIMARY KEY (jqid))');
      db_query("CREATE INDEX {job_queue}_priority_jqid_idx ON {job_queue} (priority, jqid)");
      db_query('CREATE TABLE {job_queue_functions} (
        function varchar(255) NOT NULL,
        priority smallint NOT NULL,
        PRIMARY KEY (function))');
      break; 

This code worked well on my testing environment.