Default Adopt a Hacker value per month

[Tobias Mueller <muelli cryptobitch de>]

Ahoi!

We discussed a few things around our Adopt a Hacker program during GUADEC.
If my memory serves me right, we decided a few minor things like limiting
the number of characters in the feedback form, because Paypal limits it.
I just took care about that.

I think we also talked about increasing the default amount for the AaH from 10 USD to
25 USD. The necessary change is simple, but I want to make sure that we're all on the
same page. And as raising the default value by 150% might be confusing to some people,
I want to ask: Do we want to change the value from 10 USD to 25 USD per month?

I think that I will go ahead with the change unless there is pushback within, say, a week.

Cheers,
  Tobi