Add change log to summarize repo activity (#38)

Make it visible to users when breaking changes happen in the repo

* Add changelog w/ link to previous stable version of library

CHANGELOG.md

@@ -0,0 +1,28 @@
+# Change Log
+
+All notable changes to this project will be documented in this file.
+
+## [Unreleased (`master`)][unreleased]
+
+** Breaking changes to consumer library **
+
+Major changes:
+
+* Use [functional options][options] for config
+* Remove intermediate batching of kinesis records
+* Call the callback func with each record
+* Use dep for vendoring dependencies
+* Add DDB as storage layer for checkpoints
+
+Minor changes:
+
+* remove unused buffer and emitter code
+
+[unreleased]: https://github.com/harlow/kinesis-consumer/compare/v0.1.0...HEAD
+[options]: https://dave.cheney.net/2014/10/17/functional-options-for-friendly-apis
+
+## v0.1.0 - 2017-11-20
+
+This is the last stable release of the consumer which aggregated records in `batch` before calling the callback func. 
+
+https://github.com/harlow/kinesis-consumer/releases/tag/v0.1.0