add a template for the package readme (#12499)

Co-authored-by: Erick Friis <erick@langchain.dev>

libs/cli/langchain_cli/project_template/README.md

@@ -1,4 +1,4 @@
-# LangServeHub Project Template
+# __app_name__
 
 ## Installation
 
@@ -11,11 +11,39 @@ pip install -U "langchain-cli[serve]"
 ## Adding packages
 
 ```bash
-langchain serve add $PROJECT_NAME
+# adding packages from 
+# https://github.com/langchain-ai/langchain/tree/master/templates
+langchain app add $PROJECT_NAME
+
+# adding custom GitHub repo packages
+langchain app add --repo $OWNER/$REPO
+# or with whole git string (supports other git providers):
+# langchain app add git+https://github.com/hwchase17/chain-of-verification
+
+# with a custom api mount point (defaults to `/{package_name}`)
+langchain app add $PROJECT_NAME --api_path=/my/custom/path/rag
+```
+
+Note: you remove packages by their api path
+
+```bash
+langchain app remove my/custom/path/rag
+```
+
+## Setup LangSmith (Optional)
+LangSmith will help us trace, monitor and debug LangChain applications. 
+LangSmith is currently in private beta, you can sign up [here](https://smith.langchain.com/). 
+If you don't have access, you can skip this section
+
+
+```shell
+export LANGCHAIN_TRACING_V2=true
+export LANGCHAIN_API_KEY=<your-api-key>
+export LANGCHAIN_PROJECT=<your-project>  # if not specified, defaults to "default"
 ```
 
 ## Launch LangServe
 
-```shell
-python app/server.py
+```bash
+langchain serve
 ```