Remove email outbox collection and process job; refactor email templates with rich text support and slug generation

DEVELOPMENT.md

@@ -0,0 +1,169 @@
+# PayloadCMS Mailing Plugin - Development Guide
+
+🚀 **Zero-Setup Development** with in-memory MongoDB - no database installation required!
+
+## Quick Start
+
+```bash
+# Install dependencies
+npm install
+
+# Start dev server with in-memory MongoDB
+npm run dev
+
+# Alternative: Use startup script with helpful info
+npm run dev:start
+
+# Alternative: Force memory database
+npm run dev:memory
+```
+
+## What You Get
+
+### 🎯 **Instant Setup**
+- ✅ **In-memory MongoDB** - no installation needed
+- ✅ **Example templates** automatically created
+- ✅ **Test interface** at `/mailing-test`
+- ✅ **Admin panel** at `/admin`
+- ✅ **API endpoints** for testing
+
+### 📧 **Pre-loaded Templates**
+1. **Welcome Email** - User onboarding with premium features
+2. **Order Confirmation** - E-commerce receipt with items
+3. **Password Reset** - Security email with expiring link
+
+### 🔧 **Development Tools**
+- **Web UI**: http://localhost:3000/mailing-test
+- **Admin Panel**: http://localhost:3000/admin  
+- **GraphQL Playground**: http://localhost:3000/api/graphql-playground
+- **API Endpoints**: 
+  - `POST /api/test-email` - Send/schedule emails
+  - `POST /api/process-outbox` - Process email queue
+
+## Database Options
+
+### 🚀 **In-Memory (Default - Recommended)**
+```bash
+npm run dev  # Automatic
+```
+- Zero setup required
+- Fast startup (5-10 seconds)
+- Data resets on restart
+- Perfect for development
+
+### 🔗 **External MongoDB**
+```bash
+DATABASE_URI=mongodb://localhost:27017/payload-mailing npm run dev
+```
+
+## Email Testing
+
+### MailHog (Recommended)
+```bash
+# Install and run MailHog
+go install github.com/mailhog/MailHog@latest
+MailHog
+
+# View emails at: http://localhost:8025
+```
+
+### Console Output
+The dev setup logs emails to console if no SMTP server is available.
+
+## Development Workflow
+
+1. **Start server**: `npm run dev`
+2. **Make changes** to plugin source (`src/`)
+3. **Rebuild plugin**: `npm run build` 
+4. **Test changes** in web interface or admin panel
+5. **View results** in MailHog or console
+
+## Plugin Testing
+
+### Via Web Interface
+1. Go to http://localhost:3000/mailing-test
+2. Select a template
+3. Fill in variables  
+4. Send or schedule email
+5. Check MailHog for results
+
+### Via Admin Panel
+1. Go to http://localhost:3000/admin
+2. Navigate to **Mailing > Email Templates**
+3. View/edit templates
+4. Navigate to **Mailing > Email Outbox**  
+5. Monitor email status
+
+### Via API
+```bash
+curl -X POST http://localhost:3000/api/test-email \\
+  -H "Content-Type: application/json" \\
+  -d '{
+    "type": "send",
+    "templateId": "TEMPLATE_ID",
+    "to": "test@example.com",
+    "variables": {
+      "firstName": "John",
+      "siteName": "Test App"
+    }
+  }'
+```
+
+## Startup Messages
+
+When you start the dev server, look for these messages:
+
+```
+🚀 PayloadCMS Mailing Plugin - Development Mode
+==================================================
+📦 Using in-memory MongoDB (no installation required)
+
+🔧 Starting development server...
+🚀 Starting MongoDB in-memory database...
+✅ MongoDB in-memory database started
+📊 Database URI: mongodb://***@localhost:port/payload-mailing-dev
+📧 Mailing plugin configured with test transport
+🎯 Test interface will be available at: /mailing-test
+
+✅ Example email templates created successfully
+PayloadCMS Mailing Plugin initialized successfully
+```
+
+## Troubleshooting
+
+### Server won't start
+- Ensure port 3000 is available
+- Check for Node.js version compatibility
+- Run `npm install` to ensure dependencies
+
+### Database issues
+- In-memory database automatically handles setup
+- For external MongoDB, verify `DATABASE_URI` is correct
+- Check MongoDB is running if using external database
+
+### Email issues  
+- Verify MailHog is running on port 1025
+- Check console logs for error messages
+- Ensure template variables are correctly formatted
+
+## Plugin Development
+
+The plugin source is in `src/` directory:
+- `src/plugin.ts` - Main plugin configuration
+- `src/collections/` - Email templates and outbox collections
+- `src/services/` - Mailing service with Handlebars processing
+- `src/jobs/` - Background job processing
+- `src/utils/` - Helper functions for developers
+
+Make changes, rebuild with `npm run build`, and test!
+
+## Success Indicators
+
+✅ Server starts without errors  
+✅ Admin panel loads at `/admin`  
+✅ Test interface loads at `/mailing-test`  
+✅ Templates appear in the interface  
+✅ Emails can be sent/scheduled  
+✅ Outbox shows email status  
+
+You're ready to develop and test the PayloadCMS Mailing Plugin! 🎉