propose skeleton of CHANGELOG.md (based on go-ipfs)

CHANGELOG.md

+# Eris-DB changelog
+
+## 0.12.0
+
+- Features
+
+
+- Tool changes  
+  - use glide instead of godeps for dependencies
+
+
+- General Codebase
+  - upgrade to Tendermint 0.6.0
+
+
+- Bugfixes
+
+
+- Testing
+
+
+- Documentation
+
+## 0.11.4 - _2016-04-29_