Add .env.example file with configuration template

.env.example

@@ -0,0 +1,27 @@
+# Database Configuration
+# SQLite database will be created at this path
+DATABASE_URL=sqlite:////app/storage/db/db.sqlite
+
+# FastAPI Configuration
+APP_TITLE=Simple Todo API
+APP_DESCRIPTION=A simple todo application built with FastAPI
+APP_VERSION=1.0.0
+
+# CORS Configuration
+# Comma-separated list of allowed origins for CORS
+# Use "*" to allow all origins (not recommended for production)
+CORS_ORIGINS=*
+
+# Server Configuration
+HOST=0.0.0.0
+PORT=8000
+DEBUG=false
+
+# Logging Configuration
+LOG_LEVEL=info
+
+# Security (if you add authentication later)
+# SECRET_KEY=your-secret-key-here
+# JWT_SECRET_KEY=your-jwt-secret-key-here
+# JWT_ALGORITHM=HS256
+# ACCESS_TOKEN_EXPIRE_MINUTES=30