Add instructions for GistPress on custom post meta fields

[GaryJones]

Some folks store content in custom fields (post meta), so it would be handy for them to have instructions and a code snippet they can drop in so that GistPress (in fact, any oembed parsing) can run on their particular post meta key content.

See WP_Embed::__construct() for a starting point.

[bradyvercher]

So you're looking to process oEmbeds in an arbitrary blob of content without all the formatting provided by the the_content filter?

[GaryJones]

Me personally, no, but someone asked for it :-)

Think of a CPT that has custom fields for splitting up different parts of the content - perhaps an introduction, the bulk of a code tutorial, and then a conclusion. At the moment, I don't think our shortcode or oEmbed URL would be recognised and parsed in a custom field. I realise that instructions we give are probably going to be to enable all oEmbed support for that field, rather than just GistPress, but if there's a way of also limiting it to just GistPress, even better.

I'm not saying this should be enabled by default (we don't know the post meta key anyway) - just have the instructions and example snaippet for how to enable it in the readme.