D. Ilmari Mannsåker [Mon, 3 Jun 2013 14:27:46 +0000 (15:27 +0100)]
The conditon docs are huge, making it hard to point people to the
coderef syntax when they need it, so add a header that can be linked
directly to.
C<Item::Links> is a many-to-many linking table, linking items back to
themselves in a peer fashion (without a "parent-child" designation)
+=head4 Custom join conditions
+
To specify joins which describe more than a simple equality of column
values, the custom join condition coderef syntax can be used. For
example: