:heavy_plus_sign: :eyeglasses:

Add specs (geddit :smile:)

However, there's an issue with the numeric class:
```
/Users/peterso/Projects/active_emoji/lib/active_emoji.rb:2:in `require': /Users/peterso/Projects/active_emoji/lib/active_emoji/core_ext/numeric.rb:3: class/module name must be CONSTANT (SyntaxError)
```

As an emoji isnt a capital letter, it doesn't like it as a class name...
Is this syntactic sugar actually used? If not, why include it?