Reinstate CouchbaseCache documentation. (#1357)

Closes #1356.

Author: mikereiche

src/test/java/org/springframework/data/couchbase/domain/Config.java

@@ -17,6 +17,8 @@
 package org.springframework.data.couchbase.domain;
 
 import java.lang.reflect.InvocationTargetException;
+import java.util.HashMap;
+import java.util.Map;
 
 import org.springframework.cache.annotation.EnableCaching;
 import org.springframework.context.annotation.Bean;

src/test/java/org/springframework/data/couchbase/domain/User.java

@@ -29,6 +29,8 @@
 import org.springframework.data.annotation.Version;
 import org.springframework.data.couchbase.core.mapping.Document;
 
+import java.io.Serializable;
+
 /**
  * User entity for tests
  *