Re-implemented Data Routes and Data Seeding script for testing

Due to the new auth design, I had to change the schema, seeding script and data routes. 

To see the database with test data you must: 
1.) create a new user in the front-end using Fitbit.
2.) visit /users/me and get the _id propery's value.
3.) Open seed.js and replace the value of userId var on line 9 with value from step 2.
4.) Run node seed.js and close script on completion
5.) You can now start the app.js server and login again
6.) Visit /users/activity/ to view test data - as before, date ranges can be appended to this route
EX: /users/activity/2013-04-03/2013-05-01 or  /users/activity/-/2013-05-01, ect