While there is no official Ruby style guide document similar to the Python document, the Ruby community has universally agreed upon the two-space soft indent as standard for all Ruby code, including Rails, rspec, etc. This is documented in every community-generated Ruby style guide.
Every style guide in the front-page google search endorses two spaces, and this list is by no means inclusive:
- Github style guide
- Ruby Style Guide
- Bozhidar Batsov Style Guide
- Christian Neukirchen style guide
- University of Montana style guide
- University of Virginia style guide
While this is easy enough to override myself, the default setting of the editor to one-tab is really a de facto standard of its own, and it makes passing code linting difficult for newbies who might want to contribute to projects. I know it's a bikeshed but I think it causes enough inconvenience to be filed as a bug rather than a feature request.