set_glyph_info': undefined method values'

[onnerby]

I have used fontcustom before - so I know that it works great. But in my latest development VM running ubuntu 16.04 running fontcustom compile -o /myoutputfolder/ I get the following error:

/var/lib/gems/2.3.0/gems/fontcustom-2.0.0/lib/fontcustom/generator/font.rb:42:in `set_glyph_info': undefined method `values' for #<Array:0x00000001f487c8> (NoMethodError)
Did you mean?  values_at
	from /var/lib/gems/2.3.0/gems/fontcustom-2.0.0/lib/fontcustom/generator/font.rb:19:in `generate'
	from /var/lib/gems/2.3.0/gems/fontcustom-2.0.0/lib/fontcustom/base.rb:62:in `start_generators'
	from /var/lib/gems/2.3.0/gems/fontcustom-2.0.0/lib/fontcustom/base.rb:23:in `compile'
	from /var/lib/gems/2.3.0/gems/fontcustom-2.0.0/lib/fontcustom/cli.rb:83:in `compile'
	from /var/lib/gems/2.3.0/gems/thor-0.20.0/lib/thor/command.rb:27:in `run'
	from /var/lib/gems/2.3.0/gems/thor-0.20.0/lib/thor/invocation.rb:126:in `invoke_command'
	from /var/lib/gems/2.3.0/gems/thor-0.20.0/lib/thor.rb:387:in `dispatch'
	from /var/lib/gems/2.3.0/gems/thor-0.20.0/lib/thor/base.rb:466:in `start'
	from /var/lib/gems/2.3.0/gems/fontcustom-2.0.0/bin/fontcustom:5:in `<top (required)>'
	from /usr/local/bin/fontcustom:23:in `load'
	from /usr/local/bin/fontcustom:23:in `<main>'

Anyone have a clue what I'm doing wrong?