[#94] feat: AsyncConfig 추가

common/src/main/java/itcast/async/AsyncConfig.java

@@ -0,0 +1,23 @@
+package itcast.async;
+
+import java.util.concurrent.Executor;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.scheduling.annotation.EnableAsync;
+import org.springframework.scheduling.concurrent.ThreadPoolTaskExecutor;
+
+@Configuration
+@EnableAsync
+public class AsyncConfig {
+
+    @Bean
+    public Executor mailTaskExecutor() {
+        ThreadPoolTaskExecutor executor = new ThreadPoolTaskExecutor();
+        executor.setCorePoolSize(2);
+        executor.setMaxPoolSize(3);
+        executor.setQueueCapacity(50);
+        executor.setThreadNamePrefix("MailTaskExecutor-");
+        executor.initialize();
+        return executor;
+    }
+}