Missing documentation for migrating existing sites from version 1.5 to version 2

[ShadSterling]

I'm trying to update an existing site (which I did not create) from 1.5.6 to 2.1.2, and I am having a hard time finding the documentation I need. In particular, I am unable to find any documentation of the gmaps method which is used in a Slim template, much less of how to replace that call to use the version 2 API.

The call in question is rather short:

= gmaps @map_options

Where @map_options was originally created by the to_gmaps4rails method. I've changed where that is generated to use build_markers, but I can't tell if I've done it right until I can figure out how to replace this call to gmaps.

How does the version 2 API expose the functionality of the gmaps method, or where is there documentation on migrating to version 2 that includes replacing gmaps?