Added the ability to add nicknames for users (#2981)

Co-authored-by: Mm2PL <mm2pl+gh@kotmisia.pl>
Co-authored-by: Rasmus Karlsson <rasmus.karlsson@pajlada.com>

src/controllers/nicknames/NicknamesModel.hpp

@@ -0,0 +1,25 @@
+#pragma once
+
+#include <QObject>
+
+#include "common/SignalVectorModel.hpp"
+#include "controllers/nicknames/Nickname.hpp"
+
+namespace chatterino {
+
+class NicknamesModel : public SignalVectorModel<Nickname>
+{
+public:
+    explicit NicknamesModel(QObject *parent);
+
+protected:
+    // turn a vector item into a model row
+    virtual Nickname getItemFromRow(std::vector<QStandardItem *> &row,
+                                    const Nickname &original) override;
+
+    // turns a row in the model into a vector item
+    virtual void getRowFromItem(const Nickname &item,
+                                std::vector<QStandardItem *> &row) override;
+};
+
+}  // namespace chatterino