Use deep_merge to recursively merge custom and default container options
Use deep_merge to recursively merge custom and default container options

Activesupport's `deep_merge` hash method will recursively merge hashes so
that duplicate keys will not overwrite each other. #17 introduced a change
where we now configure volume binds at create time by using the `:HostConfig`
option to do this. This makes it so that any other custom docker option that
uses `:HostConfig` (such as `:ExtraHosts`) will get overwritten in the .merge
in favor of the default volume `:Bind` configuration.

github/hoosegow,github/hoosegow