Cannot rotate image just created.

Hello! I'm trying to Rotate an image just created with `new Jimp()`, but when i try to rotate it, it doesn't works and resets also the size of that image.

I've tried with this code:
```
const myImage = new Jimp( width, height, '#FF0000', function(err,image) {
image.rotate(90);
return image;
})
```

and with this:
```
const myImage = new Jimp( width, height, '#FF0000', function(err,image) {
return image;
})
myImage.rotate(50)
```

and then i have:
`await myImage.writeAsync(path)`

But it doesn't work, it does not rotate the image