Update the community about new home at https://sleepy.bike

[mariha]

Long time ago we promised to build an alternative to WS.org (#360). Let's start rebuilding the community in https://sleepy.bike!

Places which should be updated with the info:

• [x] WarmShowers.bike page
• [x] https://gitter.im/we-love-bicycles/community room created to post updates about this project (mentioned in WS.bike page)
• [x] Gitter chat used by old WS Android developers (mentioned on main repo description)
• [x] "Open Alternative to WarmShowers.org" FB group (mentioned in WS.bike page)
• [ ] the Android app, if it is still available from Google Play Store (the message in the app + description of the app) - I won't do it (MK)

[mariha]

This is how the page looks like. There is red announcement at the top.

What text to write in the announcement? UPDATE: Welcome to sleepy.bike !!!