This renames the case_log to lettings_log as everything we've written so
far has been geared towards lettings of social housing so it makes sense to
have the name describe this. This is also a precursor to adding in stuff for
sales logs (whatever shape that takes)
Co-authored-by: James Rose <james@jbpr.net>
* API doc init
* Rename docs dir
* Try YAML
* Index page
* Chars
* Case Log
* Summaries
* Add to readme
* Add sandbox server
* Dry
* Add some 422 examples
* GET doesn't have a request body
* Accept header
* Add show method to JSON API and document not found response
* Set header default
* Add some field guidance
* Don't need a default value if we only have one enum