changes to make merging work (#48)

Author: rebasedming

src/indexer/mod.rs

@@ -17,13 +17,13 @@ mod log_merge_policy;
 mod merge_index_test;
 mod merge_operation;
 pub(crate) mod merge_policy;
-pub(crate) mod merger;
+pub mod merger;
 pub(crate) mod operation;
 pub(crate) mod prepared_commit;
 mod segment_entry;
 mod segment_manager;
 mod segment_register;
-pub(crate) mod segment_serializer;
+pub mod segment_serializer;
 pub(crate) mod segment_updater;
 pub(crate) mod segment_writer;
 pub(crate) mod single_segment_index_writer;