Exception when use({})

[yowu]

MiddlewareManager.use will throw exception if an empty object is passed as parameter.

Callstack

TypeError: _this._methodMiddlewares[methodName].push is not a function
at Array.forEach (<anonymous>)
at MiddlewareManager._applyToMethod
at Array.forEach (<anonymous>)
at Array.forEach (<anonymous>)
at MiddlewareManager.use 

Probably need to reject the empty object at the beginning.

[unbug]

Hum, please follow the doc to use Middleware object https://github.com/unbug/js-middleware#middleware-object

[yowu]

You can't rely on the caller always does the right thing. A proper edge case protection may make the library more robust. It's just my two cents.

[unbug]

Feel free to contribute your changes though.