Added /users and /users/(username)

endorsement.py

@@ -1,4 +1,14 @@
 from app import app, db
-from models import User
+from models import User, Achievement
+import json
 
-print(User.query.all())
+@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()])