added User#fetchProfile (#835)

* add User#fetchProfile

* fix merge conflicts?

src/structures/UserProfile.js

@@ -0,0 +1,49 @@
+const Collection = require('../util/Collection');
+const UserConnection = require('./UserConnection');
+
+/**
+ * Represents a user's profile on Discord.
+ */
+class UserProfile {
+  constructor(user, data) {
+    /**
+     * The owner of the profile
+     * @type {User}
+     */
+    this.user = user;
+
+    /**
+     * The Client that created the instance of the the User.
+     * @type {Client}
+     */
+    this.client = this.user.client;
+    Object.defineProperty(this, 'client', { enumerable: false, configurable: false });
+
+    /**
+     * Guilds that the ClientUser and the User share
+     * @type {Collection<Guild>}
+     */
+    this.mutualGuilds = new Collection();
+
+    /**
+     * The user's connections
+     * @type {Collection<UserConnection>}
+     */
+    this.connections = new Collection();
+
+    this.setup(data);
+  }
+
+  setup(data) {
+    for (const guild of data.mutual_guilds) {
+      if (this.client.guilds.has(guild.id)) {
+        this.mutualGuilds.set(guild.id, this.client.guilds.get(guild.id));
+      }
+    }
+    for (const connection of data.connected_accounts) {
+      this.connections.set(connection.id, new UserConnection(this.user, connection));
+    }
+  }
+}
+
+module.exports = UserProfile;