Did some checking, prior to this it would throw an exception when $PORT wasn't set in the environment. I'm not sure why you were seeing an exception when $PORT was set, as running through foreman was working fine for me.

The way I thought this would work would be:

```
#bash

export FOO="bar"
export NUM=7
export CHUNKY=false


# clj

(env/str :foo) -> "bar"
(env/str :non-existent "baz") -> "baz"

(env/int :num) -> 7
(env/int :non-existent 22) -> 22

(env/bool :chunky) -> false
(env/bool :non-existent true) -> true
```

So `env/int` and `env/bool` would do coercion / error handling on top of `env/env`.

Thoughts?