Document some best practices

[pbiggar]

For example, handling inputs/errors at the start of the handler:

match String::toUUID param
| None -> Http::badRequest "param was not a uuid"
| Some id ->
    ... // rest of handler

[sanderjson]

Is there a pattern to avoid "match hell"?

match String::toUUID param_one
| None -> Http::badRequest "param one was not a uuid"
| Some id ->
    ... // rest of handler
    match String::toUUID param_two
    | None -> Http::badRequest "param two was not a uuid"
    | Some id ->
    ... // rest of handler
    ... // etc

match MyCustonTypeSet:: [valA, valB, valC] is [id, string, int]
    | None -> Http::badRequest "Error I"
    | Some -> Http::badRequest "Error II"
    | All -> 
         ... // rest of handler

[pbiggar]

Is there a pattern to avoid "match hell"?

When we add tuples there will be, but there isn't right now.