🔧 chore(.env.example): update example values and add new configuration options

The .env.example file has been updated to include example values and new configuration options. The LANGFLOW_DATABASE_URL example has been updated to include both Postgres and SQLite examples. New configuration options have been added for cache type, server host, worker processes, server port, logging level, log file path, frontend directory path, whether to open the browser after starting the server, and whether to remove API keys from the projects saved in the database. These changes provide more flexibility and customization options for the application.

.env.example

@@ -4,5 +4,44 @@
 #        Do not commit .env file to git
 #        Do not change .env.example file
 
-# langflow_database_url=postgresql://postgres:postgres@localhost:5432/langflow
-langflow_database_url=sqlite:///./langflow.db
+# Database URL
+# Postgres example: LANGFLOW_DATABASE_URL=postgresql://postgres:postgres@localhost:5432/langflow
+# SQLite example:
+LANGFLOW_DATABASE_URL=sqlite:///./langflow.db
+
+# Cache type
+LANGFLOW_LANGCHAIN_CACHE=SQLiteCache
+
+# Server host
+# Example: LANGFLOW_HOST=127.0.0.1
+LANGFLOW_HOST=
+
+# Worker processes
+# Example: LANGFLOW_WORKERS=1
+LANGFLOW_WORKERS=
+
+# Server port
+# Example: LANGFLOW_PORT=7860
+LANGFLOW_PORT=
+
+# Logging level
+# Example: LANGFLOW_LOG_LEVEL=critical
+LANGFLOW_LOG_LEVEL=
+
+# Path to the log file
+# Example: LANGFLOW_LOG_FILE=logs/langflow.log
+LANGFLOW_LOG_FILE=
+
+# Path to the frontend directory containing build files
+# Example: LANGFLOW_FRONTEND_PATH=/path/to/frontend/build/files
+LANGFLOW_FRONTEND_PATH=
+
+# Whether to open the browser after starting the server
+# Values: true, false
+# Example: LANGFLOW_OPEN_BROWSER=true
+LANGFLOW_OPEN_BROWSER=
+
+# Whether to remove API keys from the projects saved in the database
+# Values: true, false
+# Example: LANGFLOW_REMOVE_API_KEYS=false
+LANGFLOW_REMOVE_API_KEYS=