Update storage configurations in .env.example

.env.example

@@ -85,10 +85,10 @@ EMBEDDING_BINDING_HOST=http://localhost:11434
 # AZURE_EMBEDDING_API_VERSION=2023-05-15
 
 ### Data storage selection
-# LIGHTRAG_KV_STORAGE=PGKVStorage
-# LIGHTRAG_VECTOR_STORAGE=PGVectorStorage
-# LIGHTRAG_GRAPH_STORAGE=PGGraphStorage
-# LIGHTRAG_DOC_STATUS_STORAGE=PGDocStatusStorage
+LIGHTRAG_KV_STORAGE=JsonKVStorage
+LIGHTRAG_VECTOR_STORAGE=NanoVectorDBStorage
+LIGHTRAG_GRAPH_STORAGE=NetworkXStorage
+LIGHTRAG_DOC_STATUS_STORAGE=JsonDocStatusStorage
 
 ### Oracle Database Configuration
 ORACLE_DSN=localhost:1521/XEPDB1