Challenge: Social JavaScript I

Create a model to represent the database of a new social media platform you're creating. It can be about whatever you want, but it needs the following:

At least 3 nested levels of data (including objects and arrays)
At least 1 method
Span across at least 50 lines of code. (No empty lines)
Example:

var mountainClimber = {
    name: "Bob",
    age: 31,
    favoriteClimbs: [],
    mountainClimbingFriends: [
        {
            name: "Sarah",
            age: 31,
            favoriteClimbs: [
                {
                    climbName: "Mount Everest",
                    difficulty: 10
                },
                  ... etc ...
            ]
        },
        {
            
        }
    ],
    printMountainClimber: function() {
        
    }
}

After creating the object, programmatically add 2 properties to one of the objects (doesn't matter what level of nested data you do this to)