Added simple task crud tutorial

[cve]

I'm added simple task crud tutorial to documentation which shows how to handle requests with Forms.

[lsmith77]

I think this is a good idea to have.

@xabbuh what do you think?

[xabbuh]

In general this looks good so far. I have just left some minor comments.

On a general note: I would be in favour to reword the chapter to not be in the first person perspective. That would be more inline with the rest of the documentation.