Using the alter table command in PostgreSQL, you can rename an existing table. This command will also update any references to the table such as via foreign key constraints. Just run a command like the following:

alter table ingredient_types rename to item_types;

Note that this may result in breaking a number of conventions. Foreign keys, sequences, and constraints with names eponymous to the original table will no longer follow convention despite the references being updated. These can be renamed as well if desired.

See renaming_table.sql for a full example.

See the alter table docs for more details.