structure.txt

:: users - holds the users
    _id
    username:   S,U
    password:   S
    email:      S,U
    full_name:  S
    is_disabled:B      // maybe, later
    is_admin:   B      // maybe, later 

// User.Activity --> this point to the activities collection, the Activity model 
// User.findByCredentials( {username, password} ) => User/null if password matches for the user
// User.generateAuthToken() => token for this user
// User.toJSON() => json object of User, with password and _v removed



:: routes - holds the routes that a user can choose to workout on
    _id
    route_name:     S,U
    activity_type:  S,('run','cycle',swim)
    title:          S
    cover_image:    S
    description:    S
    difficulty:     S,('easy','moderate','difficult')
    distance:       N
    time:           N
    location:       S   // maybe, later
    map_data:       S   // something that setups the map

// Route.findByRouteName( {route_name} ) => returns the route for the provided route_name
// Route.findByActivityType( {activity_type} ) => will return a list of routes that have the specified activity_type
// Route.toJSON() => json object of Route, with _v removed



:: activities - will hold the recorded activities (runs, cycling, etc)
    _id
    userId:         _id.User
    routeId:        _id.Route
    activity_type:  S,('run','cycle','swim'), 
    date_activity:  D
    distance:       N
    time_taken:     N
    pace:           N
    cal_burned:     N

// Activity.toJSON() => json object of Activity, with _v removed