Step 13/22 : RUN cd /home/$NB_USER/testbook && gem install bundler -v 1.17.2 && bundle install
---> Running in 412f6a892798
Successfully installed bundler-1.17.2
Parsing documentation for bundler-1.17.2
Installing ri documentation for bundler-1.17.2
Done installing documentation for bundler after 4 seconds
1 gem installed
/usr/lib/ruby/2.5.0/rubygems.rb:289:in `find_spec_for_exe': can't find gem bundler (>= 0.a) with executable bundle (Gem::GemNotFoundException)
from /usr/lib/ruby/2.5.0/rubygems.rb:308:in `activate_bin_path'
from /home/jovyan/gems/bin/bundle:23:in `<main>'
The command '/bin/sh -c cd /home/$NB_USER/testbook && gem install bundler -v 1.17.2 && bundle install' returned a non-zero code: 1
make: *** [Makefile:2: container] Error 1