add basic validation support

api/views/designers.py

@@ -1,6 +1,8 @@
 from flask import Blueprint, request, jsonify
 from api import db, tasks
 from api.models import Designer
+from api.validators import validate_keys_exists
+
 
 mod = Blueprint('designers', __name__, url_prefix='/designers')
 
@@ -14,6 +16,7 @@ def list():
 @mod.route("/", methods=["POST"])
 def create():
     data = request.json
+    validate_keys_exists(data, 'username', 'name')
     designer = Designer(**data)
     db.session.add(designer)
     db.session.commit()