Update README.md

Notes on branching scheme and why 1.X vs (master)

README.md

@@ -1,5 +1,12 @@
 ## gulp-sourcemaps  [![NPM version][npm-image]][npm-url] [![build status][travis-image]][travis-url] [![Test coverage][coveralls-image]][coveralls-url]
 
+### Branching
+
+- master: is latest currently (2.X) - node > 4.X
+- 1.X: is node 0.X - only issues appear to be es6
+
+Preferably, we would like move on from node 0.X as much as possible as some of the dependencies are doing so as well. Meaning for features please target master for PRs. If bugs are found to be relvant to both 1.X and master then please target PRs for the 1.X branch to make git merging easier.
+
 ### Usage
 
 #### Write inline source maps