Update README.md

Adding PostgreSQL to README as an alternative requirement

Update README.md
bc915e45 · Frank Lanitz · e6224942 · bc915e45
Commit bc915e45 authored 11 years ago by Frank Lanitz
--- a/README.md
+++ b/README.md
@@ -38,7 +38,7 @@
  
 * Ubuntu/Debian**
 * ruby 1.9.3
-* MySQL
+* MySQL or PostgreSQL
 * git
 * gitlab-shell
 * redis