@frog I’ve got the same Issue with the Image of “2016-11-25-raspbian-jessie”.
I’m logged in on the BigScreen (not with SSH) and typing via Terminal:

pi@raspberrypi:~/MagicMirror/modules/MMM-fitbit $ npm install python-shell
/home/pi/MagicMirror/modules
└── python-shell@0.4.0
npm WARN enoent ENOENT: no such file or directory, open '/home/pi/MagicMirror/modules/package.json'
npm WARN enoent ENOENT: no such file or directory, open '/home/pi/MagicMirror/modules/node_modules/node_helper/package.json'
npm WARN modules No description
npm WARN modules No repository field.
npm WARN modules No README data
npm WARN modules No license field.

I also tried this, without success:

pi@raspberrypi:~/MagicMirror $ npm install python-shell
magicmirror@2.0.0 /home/pi/MagicMirror
├── UNMET PEER DEPENDENCY grunt@1.0.1
└── python-shell@0.4.0
npm WARN grunt-yamllint@0.2.0 requires a peer of grunt@~0.4.0 but none was installed.

Anybody an Idea, what I need to do?

@leemul I tried it by my own, but it doesn’t seem to work.
I placed it 2 times on my mirror, but it doesn’t grab Infos from fitbit anymore.
Maybe it’s by design of the API / Module?