Update README instructions for comparison pages.

README.md

@@ -321,13 +321,12 @@ The feature page grabs its content automatically from the file
 ### Create or update the comparison pages (under `/comparison`)
-The [comparison page][comp] grabs its content automatically from the files under
-`data/comparisons/`.
+The [comparison page][comp] grabs its content automatically from 
+`data/comparisons.yml`.
 There are 3 files in total which you need to create or edit:
-- `data/comparisons/gitlab_vs_competitor.yml`: Create for new comparisons. Every
-  comparison page has its own yaml file. **Use underscores**
+- `data/comparisons.yml`: Update for new comparisons. Comparisons are automatically generated from the contents of this file.
 - `source/comparison/gitlab-vs-competitor.html.haml`: Create for new comparisons.
   Every comparison page has its own html file. **Use dashes**
 - `source/includes/comparison_table.html.haml`: Edit for new or existing