DATADOC-48 added new @RelatedDocument annotation

spring-data-document-core/src/main/java/org/springframework/data/document/annotation/RelatedDocument.java

@@ -0,0 +1,35 @@
+/*
+ * Copyright (c) 2011 by the original author(s).
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.data.document.annotation;
+
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+
+/**
+ * @author Thomas Risberg
+ */
+@Retention(RetentionPolicy.RUNTIME)
+@Target({
+    ElementType.FIELD
+})
+public @interface RelatedDocument {
+
+  String collection() default "";
+
+}