Social Media Post Template (Contributor's Guide)

The Contributor's Guide should provide templates for social media posts. When posting a beta or release announcement to Reddit, there should be guidance about what text to put in the message and how to link the artifact.

Here for example, there could have been some exposition which explains that it is a beta, not an actual release, and when the actual release might be downloadable or something:

https://www.reddit.com/r/cpp/comments/1ecv08e/boost_186_beta_1_is_out/