From PostgreSQL wiki
Adding a new Snippet
To add a new snippet, create a new page and add a SnippetInfo line, like this:
(see Template:SnippetInfo for more details.)
Additionally, add a line at the end specifying the language the function is written in:
The code for the snippet itself should be surrounded by a
<source lang="foo"> tag. The
lang attribute specifies the language for syntax highlighting; you'll need to experiment to find the most appropriate one. We use
lang="sql" for SQL functions and
lang="plsql" for PL/pgSQL functions.
Adding a new language category
Just add the new category link at the bottom of the page, as indicated above. This should cause the link category to appear in red. Click on that, and add this text:
This category contains functions written in the PL/Whatever language. == See also == [[Snippets]] [[Category:Languages]]
(Please make sure you use the preferred spelling for the language name.)
This will cause the page for the language to be created, listing your new function, and also the language to be listed in the "languages" category.