[docs] extension was missing

[goenning]

I was following this example, but didn't work until I appended the extension.

[coveralls]

Coverage remained the same at 85.248% when pulling 09db43f on goenning:patch-1 into a8b6864 on labstack:master.

[vishr]

I believe it uses hello as the name defined in the template, can you check if it works without the extention?

[goenning]

Yeah, it really works. I probably made some mistake before 😞