created a field named tanklevel in tanks.js

src/models/tanks.js

@@ -14,7 +14,7 @@ const tanksSchema = new mongoose.Schema({
     blockName: { type: String, default: null },
     capacity: { type: String, default: null },
     typeOfWater: { type: String, default: null },
-   
+    water_level: { type: String, default: null },
     tankLocation: { type: String, default: null },
     connections: {
         source: { type: String},