Refactor and remove sqlite and replace with MySQL

internal/models/user.go

@@ -0,0 +1,34 @@
+package models
+
+import (
+	"time"
+)
+
+type User struct {
+	Id           int
+	Username     string
+	PasswordHash string
+	IsAdmin      bool
+}
+
+// ToDo: should be in a notification model?
+type Notification struct {
+	ID        int
+	UserId    int
+	Subject   string
+	Body      string
+	IsRead    bool
+	CreatedAt time.Time
+}
+
+// ToDo: should be in a message model?
+type Message struct {
+	ID          int
+	SenderId    int
+	RecipientId int
+	Subject     string
+	Message     string
+	IsRead      bool
+	CreatedAt   time.Time
+	ArchivedAt  *time.Time
+}