Update Dockerfile

Dockerfile

@@ -71,7 +71,7 @@ ENV WHISPER_MODEL="base" \
 ENV RAG_EMBEDDING_MODEL="$USE_EMBEDDING_MODEL_DOCKER" \
     RAG_RERANKING_MODEL="$USE_RERANKING_MODEL_DOCKER" \
     SENTENCE_TRANSFORMERS_HOME="/app/backend/data/cache/embedding/models"
-
+ENV ENABLE_SIGNUP = false
 ## Hugging Face download cache ##
 ENV HF_HOME="/app/backend/data/cache/embedding/models"
 #### Other models ##########################################################