Address missing UUIDs in pre-existing users (#1042)

OpenOversight/migrations/versions/2023-07-24-1619_52d3f6a21dd9_add__uuid_column_to_users.py

@@ -5,8 +5,13 @@
 Create Date: 2023-07-24 16:19:01.375427
 
 """
+import uuid
+
 import sqlalchemy as sa
 from alembic import op
+from sqlalchemy.orm import Session
+
+from OpenOversight.app.models.database import User
 
 
 revision = "52d3f6a21dd9"
@@ -19,10 +24,17 @@ def upgrade():
         sa.Column(
             "_uuid",
             sa.String(36),
-            nullable=False,
         ),
     )
+
+    bind = op.get_bind()
+    session = Session(bind=bind)
+    for user in session.query(User).all():
+        user._uuid = str(uuid.uuid4())
+        session.commit()
+
     op.create_index(op.f("ix_users__uuid"), "users", ["_uuid"], unique=True)
+    op.alter_column("users", "_uuid", nullable=False)
 
 
 def downgrade():