Update README.md to mention Binder

README.md

@@ -44,7 +44,7 @@ This codebook largely applies to all three files. The exception is the variables
 
 ## Calculating the Big Mac index
 
-The code to calculate the index is provided as a [Jupyter Notebook][jupyter]. The code itself is written in R, a programming language designed for data manipulation and statistics. You can view the [notebook][notebook link] on github.
+The code to calculate the index is provided as a [Jupyter Notebook][jupyter]. The code itself is written in R, a programming language designed for data manipulation and statistics. You can view the [notebook][notebook link] on github, or run it with [Binder](https://mybinder.org/v2/gh/TheEconomist/big-mac-data/master?filepath=Big%20Mac%20data%20generator.ipynb).
 
 If you want to run the notebook, you’ll need to set up a few things:
 
@@ -137,6 +137,12 @@ Finally, our R script uses a few R packages you’ll need to install. The [tidyv
 > install.packages(c('tidyverse','data.table'))
 ```
 
+or
+
+```
+> source('install.R')
+```
+
 You’re all set.
 
 ### Start the notebook
@@ -161,6 +167,14 @@ $ R data-generator.R
 
 to calculate the index files. (The R script may generate numbers that are different at the last decimal place to those from the Python notebook—these differences are due to rounding errors and can be safely ignored.)
 
+### Run online
+
+The notebooks can also be run online, with no install, using [Binder](https://mybinder.org/).
+
+Jupyter+R: [![Binder](http://mybinder.org/badge.svg)](http://beta.mybinder.org/v2/gh/TheEconomist/big-mac-data/master)
+
+RStudio: [![Binder](http://mybinder.org/badge.svg)](http://beta.mybinder.org/v2/gh/TheEconomist/big-mac-data/master?urlpath=rstudio)
+
 ### Licence
 
 This software is published by _[The Economist](https://www.economist.com)_ under the [MIT licence](https://opensource.org/licenses/MIT). The data generated by _The Economist_ are available under the [Creative Commons Attribution 4.0 International License](https://creativecommons.org/licenses/by/4.0/).