doesn't work on osx

you probably know this already, but just wanted to add it to the list of would-be-awesomes! :)

```
~/dev/etc/sputnikvm-dev-web master= ⟠ npm install
npm WARN svmdev-web@ No repository field.
npm WARN svmdev-web@ No license field.
~/dev/etc/sputnikvm-dev-web master= ⟠ make shell
nix-shell
make: nix-shell: No such file or directory
make: *** [shell] Error 1
```