fix resource name handling bug

[sio4]

Hi, while I generate resource named resources, I found a bug on name detection routine Resource() function.

If I generate my resource with "resource" (buffalo generate resource resources), the structure name of generated resource is ResourcesResource and strings.Replace() on Resource() of router.go replaces first Resource and remaining sResource is used as resource name.

I replaced Replace() with TrimSuffix() and I think it is fit for the logic too.
I also added some test cases for this.

[paganotoni]

This looks good, thanks @sio4

[sio4]

Thank you all for this lovely framework! @markbates @paganotoni