Added RegisterPost in API

lib/api/api.dart

@@ -11,4 +11,23 @@ Future<dynamic> getProduct(id) async {
   var req = await Dio().get(host + '/getproduct', queryParameters: {'id': id});
   var res = req.data;
   return res;
-}
+}
+
+Future<dynamic> RegisterPost({email, password, first_name, last_name}) async {
+  Response req = await Dio().post(
+    (host + '/register'),
+    data: {
+      'email': email,
+      'password': password,
+      'first_name': first_name,
+      'last_name': last_name
+    },
+    options: Options(
+      contentType: Headers.formUrlEncodedContentType,
+      validateStatus: (status) {
+        return status! < 500;
+      },
+    ),
+  );
+  return req.statusCode;
+}