Based on official ruby 2.6.3 image (note: latest tag is still 2.3.1 for the time being)
Extras:
- build-essential (for some common gems)
- libicu-dev
- libs for bundling pg
- wkhtmltopdf 0.12.4
- nvm 0.33 with node 7.4.0
- yarn 0.24.5
- phantomjs 2.1.1
- redis-tools