feat(docker): add a quickstart compose file served from the product repo

The docs quickstart pipes a compose file hosted on the docs site straight
into `docker compose -f -`. That puts the content users execute in the docs
repo rather than here, and nothing lands on disk for them to read first.

Move the two-service stack (gateway + Postgres) into docker/ so it ships and
is reviewed alongside the code it starts, and pin the image to main-stable
instead of latest. The docs change to download-then-run follows separately.

Verified: `docker compose up -d` brings the stack healthy, /health/liveliness
returns 200, /v1/models returns 200 with the placeholder key and 401 without,
and /ui/ serves.

docker/README.md

@@ -2,6 +2,16 @@
 
 This guide provides instructions for building and running the LiteLLM application using Docker and Docker Compose.
 
+> **Just want to run LiteLLM?** This guide builds from source. To run the published
+> image instead, use `docker-compose.quickstart.yml` in this directory — the
+> two-service stack (gateway + Postgres) that the
+> [Docker quickstart](https://docs.litellm.ai/docs/proxy/docker_quick_start) documents:
+>
+> ```bash
+> curl -sSLO https://github.com/BerriAI/litellm/raw/main/docker/docker-compose.quickstart.yml
+> docker compose -f docker-compose.quickstart.yml up -d
+> ```
+
 ## Prerequisites
 
 - Docker

docker/docker-compose.quickstart.yml

@@ -0,0 +1,40 @@
+# LiteLLM quickstart stack: the gateway plus a Postgres database that stores
+# models, virtual keys, and spend logs. Used by
+# https://docs.litellm.ai/docs/proxy/docker_quick_start
+#
+#   curl -sSLO https://github.com/BerriAI/litellm/raw/main/docker/docker-compose.quickstart.yml
+#   docker compose -f docker-compose.quickstart.yml up -d
+#
+# The credentials below are placeholders for local evaluation. Before any real
+# use, set LITELLM_MASTER_KEY and LITELLM_SALT_KEY to long random values and
+# pin the image to a specific release tag.
+services:
+  litellm:
+    image: docker.litellm.ai/berriai/litellm:main-stable
+    ports:
+      - "4000:4000"
+    environment:
+      LITELLM_MASTER_KEY: sk-1234
+      LITELLM_SALT_KEY: sk-XXXXXXXXXXXXXXXX
+      DATABASE_URL: postgresql://litellm:litellm@db:5432/litellm
+      STORE_MODEL_IN_DB: "True"
+    depends_on:
+      db:
+        condition: service_healthy
+
+  db:
+    image: postgres:16
+    environment:
+      POSTGRES_USER: litellm
+      POSTGRES_PASSWORD: litellm
+      POSTGRES_DB: litellm
+    healthcheck:
+      test: ["CMD-SHELL", "pg_isready -U litellm"]
+      interval: 5s
+      timeout: 5s
+      retries: 10
+    volumes:
+      - postgres_data:/var/lib/postgresql/data
+
+volumes:
+  postgres_data: