diff --git a/olgram/migrations/models/2_20210911182503_update.sql b/olgram/migrations/models/2_20210911182503_update.sql
new file mode 100644
index 0000000..2ddc87f
--- /dev/null
+++ b/olgram/migrations/models/2_20210911182503_update.sql
@@ -0,0 +1,6 @@
+-- upgrade --
+ALTER TABLE "group_chat" ALTER COLUMN "chat_id" TYPE BIGINT USING "chat_id"::BIGINT;
+ALTER TABLE "user" ALTER COLUMN "telegram_id" TYPE BIGINT USING "telegram_id"::BIGINT;
+-- downgrade --
+ALTER TABLE "user" ALTER COLUMN "telegram_id" TYPE INT USING "telegram_id"::INT;
+ALTER TABLE "group_chat" ALTER COLUMN "chat_id" TYPE INT USING "chat_id"::INT;
diff --git a/olgram/models/models.py b/olgram/models/models.py
index 16bd2fa..b597ac9 100644
--- a/olgram/models/models.py
+++ b/olgram/models/models.py
@@ -33,7 +33,7 @@ class Bot(Model):
 
 class User(Model):
     id = fields.IntField(pk=True)
-    telegram_id = fields.IntField(index=True, unique=True)
+    telegram_id = fields.BigIntField(index=True, unique=True)
 
     class Meta:
         table = 'user'
@@ -41,7 +41,7 @@ class User(Model):
 
 class GroupChat(Model):
     id = fields.IntField(pk=True)
-    chat_id = fields.IntField(index=True, unique=True)
+    chat_id = fields.BigIntField(index=True, unique=True)
     name = fields.CharField(max_length=50)
 
     class Meta: