made changes in iot create data

src/models/tanks.js

@@ -92,7 +92,7 @@ const tankSchema = new mongoose.Schema({
 
 const IOttankSchema = new mongoose.Schema({
   hardwareId: { type: String },
-  mode: { type: Number, required: true },
+  mode: { type: String },
   tanks: [tankSchema],
   date: { type: String, required: true },
   time: { type: String, required: true }