I'm trying to work out how you pass blocks into methods.

Basically I have a method, and instead of having the user write this:

```
def user_config
    @config[:config_value] = "what they want"
end

```

I'd like them to be able to do this:

```
user_config do
    :config_value => "what they want"
end

```

But I dont know how to work with a block in the method.