Fix: add checkfirst=True for table creation, use 1 worker

Dockerfile

@@ -31,4 +31,4 @@ USER appuser
 ENV PORT=7860
 EXPOSE 7860
 
-CMD ["sh", "-c", "gunicorn app.main:app -k uvicorn.workers.UvicornWorker --bind 0.0.0.0:${PORT} --workers 2 --timeout 120"]
+CMD ["sh", "-c", "gunicorn app.main:app -k uvicorn.workers.UvicornWorker --bind 0.0.0.0:${PORT} --workers 1 --timeout 120"]

app/main.py

@@ -27,7 +27,7 @@ from .database import Base, engine, get_db
 from .models import User, DetectionRun
 from .detection_engine import run_detection
 
-Base.metadata.create_all(bind=engine)
+Base.metadata.create_all(bind=engine, checkfirst=True)
 
 app = FastAPI(title="Satellite Change Detection", version="1.0.0")