Resource RVM

Resourcing RVM seemed to fix the permission issue's. I tried installing the fallowing gems:
```ruby
...
ruby_gems             = [        # List any Ruby Gems that you want to install
  "jekyll",
  "bundler",
  "guard"
]
...
```

Both `Jekyll` and `Bundler` installed fine, but `Guard` threw an error:
```
RROR:  Error installing guard:
    ERROR: Failed to build gem native extension.

    /home/vagrant/.rvm/rubies/ruby-2.1.0/bin/ruby extconf.rb
Cannot allocate memory - /home/vagrant/.rvm/rubies/ruby-2.1.0/bin/ruby extconf.rb 2>&1

Gem files will remain installed in /home/vagrant/.rvm/gems/ruby-2.1.0/gems/nio4r-1.0.0 for inspection.
Results logged to /home/vagrant/.rvm/gems/ruby-2.1.0/extensions/x86_64-linux/2.1.0/nio4r-1.0.0/gem_make.out
```
I could however just install it manually without any hiccups after logging in (`vagrant ssh`).

#185