Installation: bundle out of date

[tur-ium]

Hi there, when trying to install I got an error when running bundle (step 3 in the installation), the version of the excel_to_code gem required is 2.1.6, but this version contains code which has become depreciated.

[tur-ium]

I managed to get it to work by running bundle update.

I suggest updating the instruction to read:

1. git clone http://github.com/decc/global-calculator
2. cd global-calculator
3. bundle update
4. bundle
5. cd model/global_2050_model
6. bundle exec rake
7. cd ../../public/gc-anim
8. wget -nH --cut-dirs=1 --no-parent -r http://d2ow8032j7094s.cloudfront.net/20150123/index.html # This downloads 1.5 GB of images
9. cd ../..