Write meta snippets for social media

[abettermap]

Description

When sharing a link to the project on social media, each service (e.g. Facebook) needs a little bit of info in order to make a good sharing preview. For example, sharing www.npr.og on FB looks like this:

And Twitter is very similar:

Our current preview looks like this:

...so could probably liven it up a little.

Related items

#23

Resolution

Need these things:

1. An image URL (e.g. from public Dropbox file) for the post preview image. The image might simply be a screenshot of the map, or a more creative approach if desired. It can be stored on Dropbox, our GH config repo, WP, doesn't matter.
2. A title, e.g. "NYC Linguistic Diversity Map"
3. A short summary which describes the project.

Long-term solution for indiv. features

The requirements above are more of an app-wide catch-all for every shared URL for map.languagemapping.org, but ideally users would see a dynamic post preview generated by a selected feature (e.g. the Language as the post title, and a truncated Description for the summary). Unfortunately this requires some server-side setup, so that enhancement will stay on the wishlist for the time being.