Add app.py with mock api implementation

app.py

@@ -0,0 +1,24 @@
+import json
+
+from flask import Flask, jsonify, request
+
+app = Flask(__name__)
+with open("data.json") as f:
+    data = json.load(f)
+
+@app.route('/all/')
+def get_all():
+    return jsonify(data)
+
+
+@app.route('/data/<data_id>', methods=["POST"])
+def set_data_point(data_id):
+    try:
+        value = request.json["value"]
+    except KeyError:
+        return jsonify({"success": False}), 400
+
+    data[data_id] = value
+    with open("data.json", "w") as f:
+        json.dump(data, f)
+    return jsonify({"success": True})