Load optional dependencies group from daru-io Gemfie

[athityakumar]

Currently, all IO related gems like spreadsheet, jsonpath, etc. are grouped under the optional group of Gemfile. They were intended to be here and not in the gemspec file due to partial-requiring use-cases. Have a look at SciRuby/daru-io#25 for more details.

Rather than adding all these dependencies to this Rails app's Gemfile, would it be possible (and better) to add the gems from daru-io's Gemfile?

Ping @Shekharrajak

[Shekharrajak]

They were intended to be here and not in the gemspec file due to partial-requiring use-cases.

@athityakumar, I didn't understand this.

[athityakumar]

The format-specific dependencies are specified in the Gemfile and not into the gemspec file. That way, a daru-io user will run gem install daru-io and only install daru-io, whereas a daru-io developer will run bundle install and install all the dependencies being used.

Currently, all dependencies are specified in the Gemfile. It'd be better if we could add them all together rather than adding them one by one.