Add models

This folder has all the models that are used for storing the API JSON data. For example, if an authentication API returns an ID and a token, the model file will look like this:

class UserData {
int id;
String token;
UserData({, this.token});
UserData.fromJson(Map<String, dynamic> json) {
id = json['id'];
token = json['token'];
Map<String, dynamic> toJson() {
final Map<String, dynamic> data = new Map<String, dynamic>();
data['id'] =;
data['token'] = this.token;
return data;