Fix missing dependancy for json

To resolve this error:

david@Workstation npmjs.org $ npm run copy

> npmjs.org@1.0.0 copy /users/david/src/npmjs.org
> ./copy.sh

Did you already run the load-views.sh script? (type 'yes')
yes
  % Total    % Received % Xferd  Average Speed   Time    Time     Time
Current
                                 Dload  Upload   Total   Spent    Left
Speed
100    41  100    41    0     0  13781      0 --:--:-- --:--:--
--:--:-- 41000
./copy.sh: line 38: json: command not found