added missing Payment model

src/models/Payment.ts

@@ -0,0 +1,15 @@
+import mongoose from 'mongoose';
+
+const PaymentSchema= new mongoose.Schema(
+  {
+    payee: {type: String, required: true},
+    amount: {type: Number, required: true},
+    for_self: {type: Number},
+    for_other: {type: Number},
+    description: {type: String},
+    added_by: {type: String},
+    date: {type: Date, required: true, default: Date.now},
+  }, {timestamps: true}
+);
+
+export const Payment = mongoose.model("Payment", PaymentSchema);