[Metasploit msfdb error | Kali Linux 2018.1]

I'm not a ruby master, but it looks like some syntax got messed up. Hopefully, the maintainer will get this fixed. Until then, I was able to work around this by commenting out the LoadError section of:

/usr/share/metasploit-framework/Rakefile

rescue LoadError
  #puts "rspec not in bundle, so can't set up spec tasks.  " \
  #     "To run specs ensure to install the development and test groups."
  #puts "Bundle currently installed '--without #{Bundler.settings.without.join(' ')}'."
  #puts "To clear the without option do `bundle install --without ''` (the --without flag with an empty string) or " \
  #     "`rm -rf .bundle` to remove the .bundle/config manually and then `bundle install`"
  puts "LoadError section commented out."
else