trying to get README to update

Author: zachary-foster

.Rbuildignore

@@ -9,3 +9,4 @@
 ^cran-comments\.md$
 ^readme_figure\.png$
 ^LICENSE$
+^README_files$

README.Rmd

@@ -1,3 +1,7 @@
+---
+output: md_document
+---
+
 [![Build Status](https://travis-ci.org/grunwaldlab/metacoder.png?branch=master)](https://travis-ci.org/grunwaldlab/metacoder?branch=master) [![codecov.io](https://codecov.io/github/grunwaldlab/metacoder/coverage.svg?branch=master)](https://codecov.io/github/grunwaldlab/metacoder?branch=master)
 [![Downloads from Rstudio mirror per month](http://cranlogs.r-pkg.org/badges/metacoder)](http://www.r-pkg.org/pkg/metacoder)
 [![Downloads from Rstudio mirror](http://cranlogs.r-pkg.org/badges/grand-total/metacoder)](http://www.r-pkg.org/pkg/metacoder)