Restoring post schema modification to add graph column

See #95

Author: cmungall

src/semsql/builder/sql_schema/semsql.sql

@@ -1601,4 +1601,4 @@ CREATE VIEW transitive_edge AS WITH RECURSIVE transitive_edge
             SELECT * FROM transitive_edge;
 
 -- patch statements table
-ALTER TABLE statements ADD COLUMN graph TEXT;
+-- ALTER TABLE statements ADD COLUMN graph TEXT;