Today I tried to use c9 ide and discovered that it does not automatically run jekyll applications. You can exectue the following in c9's terminal instead:

{% gist lyc4n/9938d27bdaa722ad349f8498db27d746 term %}

But I learned that it is possible to just create a runner specifically for a jekyll app by creating a new runner like this:

{% gist lyc4n/9938d27bdaa722ad349f8498db27d746 c9_jekyll_runner %}

To set this:

1. Go to Run > Run With > New Runner
2. Paste the above code
3. Hit Ctrl + S
4. Set the runner's name as 'Jekyll' or whatever you like

Now we can run the app using our custom runner by going to Run > Run With > Jekyll The next time, we just need to click the 'Run' button and it will use the Jekyll runner.