endorsement/endorsement.py

from app import app, db
from models import User, Achievement
import json

@app.route("/users/<username>")
def get_user(username):
    user = User.query.filter_by(username=username).first()
    if not user:
        return "{}"
    return json.dumps(user.to_obj())

@app.route("/users/")
def all_users():
    return json.dumps([user.to_obj() for user in User.query.all()])