- implement postgres connection pool

- adapt current sqlalchemy based methods to produce raw sql

app/main.py

@@ -1,3 +1,4 @@
+import asyncpg
 from contextlib import asynccontextmanager
 
 from fastapi import FastAPI, Depends
@@ -7,6 +8,7 @@ from fastapi_cache.backends.redis import RedisBackend
 from app.api.nonsense import router as nonsense_router
 from app.api.shakespeare import router as shakespeare_router
 from app.api.stuff import router as stuff_router
+from app.config import settings as global_settings
 from app.utils.logging import AppLogger
 from app.api.user import router as user_router
 from app.api.health import router as health_router
@@ -21,15 +23,26 @@ async def lifespan(_app: FastAPI):
     # Load the redis connection
     _app.redis = await get_redis()
 
+    _postgres_dsn = global_settings.postgres_url.unicode_string()
+
     try:
         # Initialize the cache with the redis connection
         redis_cache = await get_cache()
         FastAPICache.init(RedisBackend(redis_cache), prefix="fastapi-cache")
         logger.info(FastAPICache.get_cache_status_header())
+        # Initialize the postgres connection pool
+        _app.postgres_pool = await asyncpg.create_pool(
+            dsn=_postgres_dsn,
+            min_size=5,
+            max_size=20,
+        )
+        logger.info(f"Postgres pool created: {_app.postgres_pool.get_idle_size()=}")
         yield
     finally:
         # close redis connection and release the resources
         await _app.redis.close()
+        # close postgres connection pool and release the resources
+        await _app.postgres_pool.close()
 
 
 app = FastAPI(title="Stuff And Nonsense API", version="0.6", lifespan=lifespan)