fix launch issue

migrations/versions/add_connection_token.py

@@ -7,6 +7,7 @@ Create Date: 2024-03-19 13:00:00.000000
 """
 from alembic import op
 import sqlalchemy as sa
+from sqlalchemy import inspect
 
 
 # revision identifiers, used by Alembic.
@@ -17,7 +18,13 @@ depends_on = None
 
 
 def upgrade():
-    op.add_column('instances', sa.Column('connection_token', sa.String(64), nullable=True, unique=True))
+    # Get the inspector
+    inspector = inspect(op.get_bind())
+    
+    # Check if the column exists
+    columns = [col['name'] for col in inspector.get_columns('instances')]
+    if 'connection_token' not in columns:
+        op.add_column('instances', sa.Column('connection_token', sa.String(64), nullable=True, unique=True))
 
 
 def downgrade():