mjhjmtu

I've installed Vagrant in Gentoo from repository. I'm using Ruby 2.2.8. I've got following error when I was tried run Vagrant as non-root user:

pecan@tux ~ $ vagrant
/usr/lib64/ruby/site_ruby/2.2.0/rubygems/core_ext/kernel_require.rb:55:in `require': cannot load such file -- checkpoint (LoadError)
 from /usr/lib64/ruby/site_ruby/2.2.0/rubygems/core_ext/kernel_require.rb:55:in `require'
 from /usr/lib64/ruby/gems/2.2.0/gems/vagrant-1.9.8/lib/vagrant/environment.rb:7:in `<top (required)>'
 from /usr/lib64/ruby/gems/2.2.0/gems/vagrant-1.9.8/bin/vagrant:118:in `<main>'

The result of ruby /usr/lib64/ruby/gems/2.2.0/gems/vagrant-2.0.0/bin/vagrant:

pecan@tux ~ $ ruby /usr/lib64/ruby/gems/2.2.0/gems/vagrant-2.0.0/bin/vagrant
/usr/lib64/ruby/site_ruby/2.2.0/rubygems/core_ext/kernel_require.rb:55:in `require': cannot load such file -- log4r (LoadError)
 from /usr/lib64/ruby/site_ruby/2.2.0/rubygems/core_ext/kernel_require.rb:55:in `require'
 from /usr/lib64/ruby/gems/2.2.0/gems/vagrant-2.0.0/bin/vagrant:61:in `<main>'

The result of sudo vagrant:

pecan@tux ~ $ sudo vagrant
Usage: vagrant [options] <command> [<args>]

 -v, --version Print the version and exit.
 -h, --help Print this help.

Common commands:
 box manages boxes: installation, removal, etc.
 destroy stops and deletes all traces of the vagrant machine
 global-status outputs status Vagrant environments for this user
 halt stops the vagrant machine
 help shows the help for a subcommand
 init initializes a new Vagrant environment by creating a Vagrantfile
 login log in to HashiCorp's Vagrant Cloud
 package packages a running vagrant environment into a box
 plugin manages plugins: install, uninstall, update, etc.
 port displays information about guest port mappings
 powershell connects to machine via powershell remoting
 provision provisions the vagrant machine
 push deploys code in this environment to a configured destination
 rdp connects to machine via RDP
 reload restarts vagrant machine, loads new Vagrantfile configuration
 resume resume a suspended vagrant machine
 snapshot manages snapshots: saving, restoring, etc.
 ssh connects to machine via SSH
 ssh-config outputs OpenSSH valid configuration to connect to the machine
 status outputs status of the vagrant machine
 suspend suspends the machine
 up starts and provisions the vagrant environment
 validate validates the Vagrantfile
 version prints current and latest Vagrant version

For help on any individual command run `vagrant COMMAND -h`

Additional subcommands are available, but are either more advanced
or not commonly used. To see all subcommands, run the command
`vagrant list-commands`.

I'm using the system Ruby. As you can see Vagrant with sudo works but I've question why I'm unable to run Vagrant as non-root user? What should I do to be able run Vagrant as non-root user?

I'm counting for help.