Added Contact Model (#34)

src/structures/BusinessContact.js

@@ -0,0 +1,18 @@
+'use strict';
+
+const Contact = require('./Contact');
+
+/**
+ * Represents a Business Contact on WhatsApp
+ * @extends {Contact}
+ */
+class BusinessContact extends Contact {
+    _patch(data) {
+        this.businessProfile = data.businessProfile;
+
+        return super._patch(data);
+    }
+
+}
+
+module.exports = BusinessContact;