Merge pull request #209 from run-llama/jerry/edit_readme

add .env instructions 

templates/types/simple/fastapi/README-template.md

@@ -9,6 +9,13 @@ poetry install
 poetry shell
 ```
 
+By default, we use the OpenAI LLM (though you can customize, see app/api/routers/chat.py). As a result you need to specify an `OPENAI_API_KEY` in an .env file in this directory.
+
+Example `backend/.env` file:
+```
+OPENAI_API_KEY=<openai_api_key>
+```
+
 Second, run the development server:
 
 ```

templates/types/streaming/fastapi/README-template.md

@@ -9,6 +9,13 @@ poetry install
 poetry shell
 ```
 
+By default, we use the OpenAI LLM (though you can customize, see app/api/routers/chat.py). As a result you need to specify an `OPENAI_API_KEY` in an .env file in this directory.
+
+Example `backend/.env` file:
+```
+OPENAI_API_KEY=<openai_api_key>
+```
+
 Second, run the development server:
 
 ```