Added Gemfile, instructions on how to preview site locally with Jekyll

Gemfile

@@ -0,0 +1,2 @@
+source 'https://rubygems.org'
+gem 'github-pages', group: :jekyll_plugins

README.md

@@ -102,6 +102,25 @@ If not, add your task or dataset to the respective section of the corresponding
 | ------------- | :-----:| --- | --- | 
 |  |  |  | | 
 
+**Important note:** We are currently transitioning from storing results in tables (as above) to using
+[YAML](https://en.wikipedia.org/wiki/YAML) files for their greater flexibility. This will allow us to 
+highlight additional attributes and have interesting visualizations of results down the line.
+
+If the results for your task are already stored in a YAML file, you can simply extend the YAML file
+using the same fields as the existing entries. To check that the resulting table looks as expected,
+you can build the site locally using Jekyll by following the steps detailed
+[here](https://help.github.com/articles/setting-up-your-github-pages-site-locally-with-jekyll/#requirements):
+
+1. Check whether you have Ruby 2.1.0 or higher installed with `ruby --version`, otherwise [install it](https://www.ruby-lang.org/en/downloads/).
+On OS X for instance, this can be done with `brew install ruby`.
+2. Install Bundler `gem install bundler`. If you run into issues with installing bundler on OS X, have a look
+[here](https://bundler.io/v1.16/guides/rubygems_tls_ssl_troubleshooting_guide.html) for troubleshooting tips. Also try refreshing
+the terminal.
+3. Install Jekyll: `bundle install`
+4. Clone the repo locally: `git clone https://github.com/sebastianruder/NLP-progress`
+5. Navigate to the repo with `cd NLP-progress` and run the Jekyll site locally: `bundle exec jekyll serve`
+6. You can now preview the local Jekyll site in your browser at `http://localhost:4000`.
+
 ### Things to do
 
 - Add a column for code (see above) to each table and a link to the source code to each method.