Verify lessons with Cheddar work at all

[honzajavorek]

The Academy itself admits the following:

Cheddar website was changed and the below example no longer works there. Nonetheless, the general approach is still viable on some websites even though introspection is disabled on most.

Readers of the Academy report:

It seems like cheddar.com does not use GraphQL anymore.

I'd prefer teaching in an isolated environment and maintain a few real world exercises which are not as expensive to rework as a whole lesson or even course is.