fix: typo.

Author: liqiang-fit2cloud

installer/Dockerfile

@@ -44,7 +44,7 @@ ENV MAXKB_VERSION="${DOCKER_IMAGE_TAG} (build at ${BUILD_AT}, commit: ${GITHUB_C
     MAXKB_DB_MAX_OVERFLOW=80 \
     MAXKB_REDIS_HOST=127.0.0.1 \
     MAXKB_REDIS_PORT=6379 \
-    MAXKB_REDIS_DATABASE=0 \
+    MAXKB_REDIS_DB=0 \
     MAXKB_REDIS_PASSWORD=${REDIS_PASSWORD} \
     MAXKB_EMBEDDING_MODEL_PATH=/opt/maxkb-app/model/embedding \
     MAXKB_EMBEDDING_MODEL_NAME=/opt/maxkb-app/model/embedding/shibing624_text2vec-base-chinese \