Add postgres to devcontainer / compose

.devcontainer/devcontainer.json

@@ -1,10 +1,13 @@
 {
     "$schema": "https://containers.dev/implementors/json_schema/",
-    "build": {
-        "dockerfile": "Dockerfile"
+    "dockerComposeFile": "docker-compose.yml",
+    "service": "app",
+    "workspaceFolder": "/workspaces/firehose",
+    "remoteUser": "root",
+    "containerEnv": {
+        "DB_HOST": "db",
+        "HOME": "/home/vscode"
     },
-    "remoteUser": "vscode",
-    "runArgs": [],
     "features": {
         "ghcr.io/devcontainers/features/python:1": {},
         "ghcr.io/jsburckhardt/devcontainer-features/uv:1": {},

.devcontainer/docker-compose.yml

@@ -0,0 +1,28 @@
+services:
+  app:
+    build:
+      context: .
+      dockerfile: Dockerfile
+    volumes:
+      - ..:/workspaces/firehose:cached
+    command: sleep infinity
+    depends_on:
+      db:
+        condition: service_healthy
+
+  db:
+    image: postgres:16
+    restart: unless-stopped
+    environment:
+      POSTGRES_USER: postgres
+      POSTGRES_PASSWORD: postgres
+    volumes:
+      - pgdata:/var/lib/postgresql/data
+    healthcheck:
+      test: ["CMD-SHELL", "pg_isready -U postgres"]
+      interval: 5s
+      timeout: 5s
+      retries: 5
+
+volumes:
+  pgdata:

app/config/dev.exs

@@ -4,7 +4,7 @@ import Config
 config :firehose, Firehose.Repo,
   username: "postgres",
   password: "postgres",
-  hostname: "localhost",
+  hostname: System.get_env("DB_HOST") || "localhost",
   database: "firehose_dev",
   stacktrace: true,
   show_sensitive_data_on_connection_error: true,

app/config/test.exs

@@ -8,7 +8,7 @@ import Config
 config :firehose, Firehose.Repo,
   username: "postgres",
   password: "postgres",
-  hostname: "localhost",
+  hostname: System.get_env("DB_HOST") || "localhost",
   database: "firehose_test#{System.get_env("MIX_TEST_PARTITION")}",
   pool: Ecto.Adapters.SQL.Sandbox,
   pool_size: System.schedulers_online() * 2

test.sh

@@ -0,0 +1,8 @@
+#!/bin/bash
+set -e
+export ELIXIR_ERL_OPTIONS="+fnu"
+/home/vscode/.local/bin/mise trust /workspaces/firehose/mise.toml 2>/dev/null
+eval "$(/home/vscode/.local/bin/mise activate bash)"
+cd /workspaces/firehose/app
+mix deps.get
+mix test