Update TODO list.

Author: bmomjian

doc/TODO

@@ -1,6 +1,6 @@
 TODO list for PostgreSQL
 ========================
-Last updated:		Wed Sep  5 20:04:07 EDT 2001
+Last updated:		Wed Sep  5 23:46:02 EDT 2001
 
 Current maintainer:	Bruce Momjian (pgman@candle.pha.pa.us)
 
@@ -126,6 +126,7 @@ INDEXES
 * Prevent index uniqueness checks when UPDATE does not modifying column
 * Add bitmap indexes [performance]
 * Improve handling of index scans for NULL
+* Allow GIST indexes to handle NULLs
 
 SYSTEM TABLES