feat: setup postgres with docker compose (#85)

* feat: add postgres to docker compose

* feat: run migrations via entrypoint

* chore: tidy .env.example

* fix: allow empty strings for optional envs

* fix: remove external from kan-network

* chore: update readme

apps/web/entrypoint.sh

@@ -0,0 +1,16 @@
+#!/bin/sh
+
+# Run migrations from the Turborepo root context
+echo "Running database migrations..."
+# Navigate to the Turborepo root to run the db:migrate command
+pnpm --prefix /app db:migrate
+
+# Check if migration was successful
+if [ $? -ne 0 ]; then
+  echo "\nDatabase migration failed! Exiting."
+  exit 1
+fi
+
+echo "\nStarting Next.js application..."
+# Start the Next.js application from the web app's directory
+exec node .next/standalone/apps/web/server.js