Add Ordered to RegistrationBean

Fixes gh-507

spring-boot/src/main/java/org/springframework/boot/context/embedded/RegistrationBean.java

@@ -22,6 +22,7 @@ import java.util.Map;
 import javax.servlet.Registration;
 
 import org.springframework.core.Conventions;
+import org.springframework.core.Ordered;
 import org.springframework.util.Assert;
 
 /**
@@ -32,10 +33,12 @@ import org.springframework.util.Assert;
  * @see FilterRegistrationBean
  * @see ServletListenerRegistrationBean
  */
-public abstract class RegistrationBean implements ServletContextInitializer {
+public abstract class RegistrationBean implements ServletContextInitializer, Ordered {
 
 	private String name;
 
+	private int order = Ordered.LOWEST_PRECEDENCE;
+
 	private boolean asyncSupported = true;
 
 	private Map<String, String> initParameters = new LinkedHashMap<String, String>();
@@ -113,4 +116,19 @@ public abstract class RegistrationBean implements ServletContextInitializer {
 		}
 	}
 
+	/**
+	 * @param order the order to set
+	 */
+	public void setOrder(int order) {
+		this.order = order;
+	}
+
+	/**
+	 * @return the order
+	 */
+	@Override
+	public int getOrder() {
+		return this.order;
+	}
+
 }