"supported protobuf version" in README seems outdated

[doudou]

master's README claims 2.5, while the travis tests run with PROTOBUF_VERSION=2.6.1 and the specs include the google unit tests files that have oneof (a 2.6+ feature).

[henriklb]

To add to that,

In order to compile I had to specify the plugin, this was not intuitive for a noob like me. Maybe update the README to inform of this?
protoc --plugin=protoc-gen-ruby-protobuf=/var/lib/gems/2.3.0/gems/protobuf-3.8.4/bin/protoc-gen-ruby -I . --ruby-protobuf_out . test.proto

[zachd]

Same here, it looks like Google have added support for --ruby_out in protoc which generates their own code using the google-protobuf gem. This project now requires a specific plugin flag to be set in the protoc compiler command.

[dsimmsatsquare]

Aside for anyone else who gets excited about support from Google for ruby: that only supports version 3 (unlike ruby-protobuf)