Added files of the Todo app

Backend/models/Todo.js

@@ -0,0 +1,37 @@
+import mongoose from 'mongoose';
+
+const todoSchema = new mongoose.Schema({
+  title: {
+    type: String,
+    required: true,
+    trim: true,
+    maxlength: 200
+  },
+  description: {
+    type: String,
+    trim: true,
+    maxlength: 1000
+  },
+  completed: {
+    type: Boolean,
+    default: false
+  },
+  priority: {
+    type: String,
+    enum: ['low', 'medium', 'high'],
+    default: 'medium'
+  },
+  dueDate: {
+    type: Date,
+    required: true
+  },
+  userId: {
+    type: mongoose.Schema.Types.ObjectId,
+    ref: 'User',
+    required: true
+  }
+}, {
+  timestamps: true
+});
+
+export default mongoose.model('Todo', todoSchema);