Build error trying to setup workbench environment

Hi, I’m just trying this out and running into a build error, as I’m new to Ruby/Rails I hope someone can help me out. I’m going through the steps described in
Local development environment with workbench
Prepare the workbench
Step 3: Build the images

wieland@w2:~/Work/tech/peatio/workbench$ make build
Rendering configuration…
Traceback (most recent call last):
2: from /home/wieland/.rbenv/versions/2.5.3/bin/bundle:23:in <main>' 1: from /home/wieland/.rbenv/versions/2.5.3/lib/ruby/2.5.0/rubygems.rb:308:inactivate_bin_path’
/home/wieland/.rbenv/versions/2.5.3/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)
Makefile:18: recipe for target ‘config’ failed
make: *** [config] Error 1
wieland@w2:~/Work/tech/peatio/workbench$ rbenv which bundle
wieland@w2:~/Work/tech/peatio/workbench$ rbenv which bundler
wieland@w2:~/Work/tech/peatio/workbench$ which bundle
wieland@w2:~/Work/tech/peatio/workbench$ which bundler

Solved. Had to update the ruby system.