execjs depends on javascript-engine

[jonaslejon]

$ bundle exec sidekiq
There was an error while trying to load the gem 'uglifier'.
Gem Load Error is: Could not find a JavaScript runtime. See https://github.com/rails/execjs for a list of available runtimes.
Backtrace for gem load error is:
..cut..

[m0nad]

Try to install nodejs:
sudo apt-get install nodejs