Added windows CI

.Rbuildignore

@@ -4,4 +4,5 @@ Makefile
 man-roxygen
 man-roxygen/^.*\.Rproj$
 ^\.Rproj\.user$
-vignettes/margins.sty
+vignettes/margins.sty
+appveyor.yml

README.md

@@ -1,4 +1,4 @@
-[![Build Status](https://travis-ci.org/ropensci/plotly.png?branch=master)](https://travis-ci.org/ropensci/plotly)
+[![Build Status](https://travis-ci.org/ropensci/plotly.png?branch=master)](https://travis-ci.org/ropensci/plotly)  [![Build status](https://ci.appveyor.com/api/projects/status/4m5gq5hbjqcgkpep)](https://ci.appveyor.com/project/karthik/plotly)
 
 plotly: Scientific Graphing Library 
 ======

appveyor.yml

@@ -0,0 +1,18 @@
+init:
+  ps: |
+        $ErrorActionPreference = "Stop"
+        Invoke-WebRequest http://raw.github.com/krlmlr/r-appveyor/master/scripts/appveyor-tool.ps1 -OutFile "..\appveyor-tool.ps1"
+        Import-Module '..\appveyor-tool.ps1'
+
+install:
+  ps: Bootstrap
+
+build_script:
+  - travis-tool.sh install_deps
+
+test_script:
+  - travis-tool.sh run_tests
+
+on_failure:
+  - travis-tool.sh dump_logs
+