Version Parity

[MtnBiker]

The Readme in the Version Parity section could be interpreted to mean that leaflet-rails is up to v0.7.7. But you're current so the section should mention that.
Maybe a line at the top could be change to: leaflet-rails tries to keep version parity with leaflet.js and currently at Leaflet 1.4. However in the past version parity was not always possible. Discrepancies have been noted below.

Or even better the whole section could be:
leaflet-rails keeps version parity with leaflet.js and currently at Leaflet 1.4. Before v0.7.7 the versions were not always in sync.

I don't know if you even need the last sentence.