therubyracer dependency makes handlebars.rb incompatible with Apple M1 processors

[rosatolen]

Although therubyracer can be set up with Rosetta emulation, there are runtime issues with it. While searching for a solution, I discovered that therubyracer is no longer maintained.

therubyracer should be switched out with another suitable JS runner so that handlebars.rb can be used into the future.

[gi]

For anyone attempting to fix this issue, be aware of the known issue with execjs and mini_racer. These libraries can likely be used, but the communication method between Ruby and JS needs to be altered.

See rubyjs/mini_racer#183

[feldpost]

If you are interested, we have ported handlebars.rb to mini_racer: https://github.com/combinaut/minibars

[gi]

I also wrote an implementation using mini_racer: https://github.com/gi/handlebars-ruby.