Switch from socket.io to REST for cadence streaming in attempt to fix timeout issue

db.py

@@ -59,3 +59,7 @@ class DataBase():
 
     def get_device(self, device_id):
         return self.execute('SELECT * FROM device WHERE id = %s', [device_id], one=True)
+
+    def insert_cadence(self, rpm, device_id):
+        self.execute('INSERT INTO cadence (rpm, device_id) VALUES (%s, %s)',
+                     [rpm, device_id], commit=True)