Update to use bigger avatar image and twitter now use screen_name based profile image url

Author: jackycute

lib/models/user.js

@@ -64,10 +64,10 @@ module.exports = function (sequelize, DataTypes) {
                         photo = 'https://graph.facebook.com/' + profile.id + '/picture';
                         break;
                     case "twitter":
-                        photo = profile.photos[0].value;
+                        photo = 'https://twitter.com/' + profile.username + '/profile_image?size=bigger';
                         break;
                     case "github":
-                        photo = 'https://avatars.githubusercontent.com/u/' + profile.id + '?s=48';
+                        photo = 'https://avatars.githubusercontent.com/u/' + profile.id + '?s=96';
                         break;
                     case "gitlab":
                         photo = profile.avatarUrl;