Configure RAM and CPU usage at Vagrant 2 Virtualbox VM

Here's how you can increase VM limits:

Vagrant.configure("2") do |config|
 # ... 
  config.vm.provider :virtualbox do |virtualbox|
    # allocate 1024 mb RAM
    virtualbox.customize ["modifyvm", :id, "--memory", "1024"] 
    # allocate max 50% CPU
    virtualbox.customize ["modifyvm", :id, "--cpuexecutioncap", "50"]
  end
end