refactor '__main__' block and update README

Signed-off-by: Grant Ramsay <seapagan@gmail.com>

Author: seapagan

README.md

@@ -48,6 +48,12 @@ Run the server using `Uvicorn`:
 uvicorn main:app --reload
 ```
 
+> You can also run the server by just executing the `main.py` file:
+>
+> ```console
+> python main.py
+> ```
+
 Then open your browser at [http://localhost:8000](http://localhost:8000).
 
 There is only one endpoint available: `/users`. It returns a list of all users

main.py

@@ -1,7 +1,7 @@
 """An example of using FastAPI with Async SQLAlchemy 2."""
-import subprocess
 from contextlib import asynccontextmanager
 
+import uvicorn
 from fastapi import Depends, FastAPI
 from sqlalchemy import select
 
@@ -42,4 +42,4 @@ async def get_users(session=Depends(get_db)):
 
 
 if __name__ == "__main__":
-    subprocess.call(["uvicorn", "main:app", "--reload"])
+    uvicorn.run("main:app", reload=True)