Ensure Chamber loads Chamber::Instance in bin/chamber

Fixes #29.

The problem is that https://github.com/thekompanee/chamber/blob/master/lib/chamber/commands/initialize.rb#L13 calls `Chamber.configuration` which is part of the `Chamber::Instance` class that the `Chamber` singleton delegates to via method_missing. Since the `bin/chamber` file only includes `chamber/binary/runner`, the `Chamber` singleton is never correctly initiated.