add initial JSON section

Still a work in progress for this issue. Please comment and review

Be gentle my first pull request
This doesn't actually work. It needs to be:

```python
'{"first_name":"Guido","last_name":"Rossum"}'
```

Note the types of quotes used. You should also assign this to `json_string` so it's usage in the next example makes sense. Alternatively, don't use the variable name and just copy and paste the string into the call to `json.loads`