create default avatar, admin, and deleted user on first run

app/db.py

@@ -200,6 +200,16 @@ class Model:
         return None
 
 
+    @classmethod
+    def count(cls, conditions = None):
+        qb = db.QueryBuilder(cls.table).select("COUNT(*) AS c")
+        if conditions is not None:
+            qb.where(conditions)
+
+        result = qb.first()
+        return result["c"] if result else 0
+
+
     def update(self, data):
         qb = db.QueryBuilder(self.table)\
             .where({"id": self._data["id"]})