Add DATABASE_URL env var support for EmDash

- Add .env.example documenting SQLite/PostgreSQL/MySQL config
- Add src/lib/db.ts with getDatabaseConfig() helper that parses
  DATABASE_URL and returns the appropriate db config
- Update astro.config.mjs to use getDatabaseConfig() instead of
  hardcoded sqlite path

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

.env.example

@@ -0,0 +1,36 @@
+# EmDash Environment Variables
+# Copy this file to .env and fill in your values
+
+# ===========================================
+# DATABASE (choose one)
+# ===========================================
+
+# SQLite (default - local file)
+# DATABASE_URL=file:./storage/data.db
+
+# PostgreSQL
+# DATABASE_URL=postgresql://user:password@host:5432/emdash
+
+# MySQL
+# DATABASE_URL=mysql://user:password@host:3306/emdash
+
+# ===========================================
+# SESSION SECRET (required for production)
+# ===========================================
+# Generate with: openssl rand -base64 32
+# SESSION_SECRET=your-secret-key-here
+
+# ===========================================
+# S3 STORAGE (optional - for cloud storage)
+# ===========================================
+# AWS S3
+# S3_BUCKET=my-uploads
+# S3_REGION=us-east-1
+# AWS_ACCESS_KEY_ID=xxx
+# AWS_SECRET_ACCESS_KEY=xxx
+
+# Cloudflare R2
+# R2_ACCOUNT_ID=xxx
+# R2_ACCESS_KEY_ID=xxx
+# R2_SECRET_ACCESS_KEY=xxx
+# R2_BUCKET=my-uploads

astro.config.mjs

@@ -3,7 +3,7 @@ import react from "@astrojs/react";
 import { auditLogPlugin } from "@emdash-cms/plugin-audit-log";
 import { defineConfig, fontProviders } from "astro/config";
 import emdash, { local } from "emdash/astro";
-import { sqlite } from "emdash/db";
+import { getDatabaseConfig } from "./src/lib/db.ts";
 
 export default defineConfig({
 	output: "server",
@@ -17,7 +17,7 @@ export default defineConfig({
 	integrations: [
 		react(),
 		emdash({
-			database: sqlite({ url: "file:./storage/data.db" }),
+			database: getDatabaseConfig(),
 			storage: local({
 				directory: "./storage/uploads",
 				baseUrl: "/_emdash/api/media/file",

src/lib/db.ts

@@ -0,0 +1,37 @@
+import { sqlite, postgres, mysql } from "emdash/db";
+
+/**
+ * Database configuration from environment variables.
+ *
+ * Supports:
+ * - SQLite: DATABASE_URL=file:./storage/data.db
+ * - PostgreSQL: DATABASE_URL=postgresql://user:pass@host:5432/db
+ * - MySQL: DATABASE_URL=mysql://user:pass@host:3306/db
+ */
+export function getDatabaseConfig() {
+	const url = process.env.DATABASE_URL;
+
+	if (!url) {
+		// Default to SQLite
+		return sqlite({ url: "file:./storage/data.db" });
+	}
+
+	if (url.startsWith("file:")) {
+		// SQLite
+		return sqlite({ url: url });
+	}
+
+	if (url.startsWith("postgresql:")) {
+		// PostgreSQL
+		return postgres({ connectionString: url });
+	}
+
+	if (url.startsWith("mysql:")) {
+		// MySQL
+		return mysql({ connectionString: url });
+	}
+
+	// Fallback to SQLite
+	console.warn(`Unknown DATABASE_URL protocol, falling back to SQLite`);
+	return sqlite({ url: "file:./storage/data.db" });
+}