feat(Countries): Adding countries endpoint

lib/Models/states.model.js

@@ -0,0 +1,12 @@
+const mongoose = require('mongoose');
+const { Schema } = mongoose;
+
+const schema = new Schema({
+    country_name: { type: String},
+    country_code: { type: String },
+    state_name: { type: String, required: true },
+    state_code: { type: String }
+});
+
+module.exports = mongoose.model( "states", schema );
+