Mismatch in format used by elm-bridge and Aeson

My setup is that I have a websocket server running in Haskell, accepting commands encoded into JSON by elm-bridge's encoders on the client-side, and decoded by Aeson on the server-side.

On the server, in Haskell I have my data types defined as follows:
```haskell
{-# LANGUAGE DeriveGeneric, DeriveAnyClass #-}

module Domain.Data where

import GHC.Generics
import Data.Aeson

data WebSocketMessage = WebSocketMessage String deriving (Eq, Show, Generic, ToJSON, FromJSON)
data WebSocketCommand = WebSocketCommand Command deriving (Eq, Show, Generic, ToJSON, FromJSON)

data Id = Id String deriving (Eq, Show, Ord, Generic, ToJSON, FromJSON)
data EditDone = EditDone Id DoneState DoneState deriving (Eq, Show, Generic, ToJSON, FromJSON)
data DoneState = Done | NotDone deriving (Eq, Show, Generic, ToJSON, FromJSON)

data Command
= EditDoneCommand EditDone
| OtherCommands
```

and these are decoded in the server via:
```haskell
let mCmd :: Maybe WebSocketCommand = Json.decode msg
```

Note that I'm using the Generic, ToJSON, and FromJSON automatic derivations for the server-side decoding via Aeson.

Also in Haskell I'm executing elm-bridge, like so:

```haskell
{-# LANGUAGE TemplateHaskell #-}
import Elm.Derive
import Elm.Module

import Data.Proxy

import Domain.Data

deriveElmDef defaultOptions ''EditDone
deriveElmDef defaultOptions ''Command
deriveElmDef defaultOptions ''Id
deriveElmDef defaultOptions ''DoneState

main :: IO ()
main = do
putStrLn $ makeElmModule "Domain.Data"
[ DefineElm (Proxy :: Proxy EditDone)
, DefineElm (Proxy :: Proxy Command)
, DefineElm (Proxy :: Proxy Id)
, DefineElm (Proxy :: Proxy DoneState)

```

Note that I'm only running "deriveElmDef" as the Aeson derivations are already done separately. This took a bit of working out on my part as I don't think it's documented, so it may well be that I got this bit wrong; I couldn't get my program to compile any other way though!

Right, now to the meat; I added some tracing to my server and I can see that I receive JSON in the form:
```json
{"EditDoneCommand":["foo","NotDone","Done"]}
```

But when Aeson decodes it I get a Nothing. So I added an output for Aeson's encoding, and it turns out that Aeson outputs a different format:

```json
{"tag":"EditDoneCommand","contents":["foo","NotDone","Done"]}
```

Which looks like a longer form.

Given that I'm not familiar with Aeson, have I misconfigured something in my enthusiasm to get the thing compiling? Do you know how I can remedy this situation?

Thanks in advance for any advice!

PS. I have elm-bridge 0.4.0 and Aeson 0.11.2.1 installed.