Updates Vagrantfile to install Ruby 2.1.0

I've downloaded the code and after running vagrant up I received the following error message:

```
Your Ruby version is 1.9.3, but your Gemfile specified 2.1.0
The following SSH command responded with a non-zero exit status.
Vagrant assumes that this means the command failed!

chmod +x /tmp/vagrant-shell && /tmp/vagrant-shell

Stdout from the command:

Your Ruby version is 1.9.3, but your Gemfile specified 2.1.0


Stderr from the command:

stdin: is not a tty
```

This commit changes the version of ruby to install from ruby-1.9.3-p392 to ruby-2.1.0 the same version on Gemfile