build missing 'slimrb'

[ericlink]

love shiba! was trying to add zoom in and out for a PR, but running into a build issue w/ rake. not familiar w/ the ruby build stuff, but getting issue below, 'slimrb' command doesn't exist

$ npm run start

> shiba@1.2.1 start /Users/elink/Source/fed/electron/shiba
> npm run dep && npm run build && npm run show-readme

> shiba@1.2.1 dep /Users/elink/Source/fed/electron/shiba
> rake dep

> shiba@1.2.1 build /Users/elink/Source/fed/electron/shiba
> rake build

rake aborted!
'slimrb' command doesn't exist
/Users/elink/Source/fed/electron/shiba/Rakefile:20:in `ensure_cmd'
/Users/elink/Source/fed/electron/shiba/Rakefile:43:in `block in <top (required)>'
Tasks: TOP => build => compile => build_slim
(See full trace by running task with --trace)
npm ERR! code ELIFECYCLE
npm ERR! errno 1
npm ERR! shiba@1.2.1 build: `rake build`
npm ERR! Exit status 1
npm ERR!
npm ERR! Failed at the shiba@1.2.1 build script.
npm ERR! This is probably not a problem with npm. There is likely additional logging output above.

npm ERR! A complete log of this run can be found in:
npm ERR!     /Users/elink/.npm/_logs/2019-03-07T20_58_46_672Z-debug.log
npm ERR! code ELIFECYCLE
npm ERR! errno 1
npm ERR! shiba@1.2.1 start: `npm run dep && npm run build && npm run show-readme`
npm ERR! Exit status 1
npm ERR!
npm ERR! Failed at the shiba@1.2.1 start script.
npm ERR! This is probably not a problem with npm. There is likely additional logging output above.

npm ERR! A complete log of this run can be found in:
npm ERR!     /Users/elink/.npm/_logs/2019-03-07T20_58_46_709Z-debug.log

[rhysd]

Please follow the build instruction

https://github.com/rhysd/Shiba/blob/4f31c9b5704f891e313abfe557b0492182761728/docs/installation.md#for-development

[ericlink]

duh, thank you!