Work towards #56: Add permalink to every pattern

This makes cleaner URLs thanks to jekyll

specification/index.md

@@ -2,6 +2,7 @@
 layout: pattern
 title: Specification
 folder: specification
+permalink: /patterns/specification/
 categories: pattern_cat
 tags: pattern_tag
 ---
@@ -16,4 +17,4 @@ order
 **Applicability:** Use the Specification pattern when
 
 * you need to select a subset of objects based on some criteria, and to refresh the selection at various times
-* you need to check that only suitable objects are used for a certain role (validation)
+* you need to check that only suitable objects are used for a certain role (validation)