add email to user schema

models/users.js

@@ -12,6 +12,11 @@ const userSchema = new Schema({
     type: String,
     required: true
   },
+  email: {
+      type: String,
+      required: true,
+      unique: true
+  },
   role: String,
   phone:  {
     type: String,
@@ -25,4 +30,4 @@ const userSchema = new Schema({
   resources: [{type: ObjectId, ref: 'Resource'}]
 });
 
-mongoose.model('Users', userSchema);
\ No newline at end of file
+mongoose.model('Users', userSchema);