Strip leading and trailing slug punctuation.

lib/slug.rb

@@ -23,6 +23,7 @@ module Slug
     str.gsub!(/[^a-z0-9 -]/, '')
     str.gsub!(/\s+/, '-')
     str.gsub!(/\-+/, '-')
+    str.gsub!(/^-|-$/, '')
 
     str
   end

spec/components/slug_spec.rb

@@ -27,6 +27,13 @@ describe Slug do
     Slug.for("a....b.....c").should == "a-b-c"
   end
 
+  it 'strips trailing punctuation' do
+    Slug.for("hello...").should == "hello"
+  end
+
+  it 'strips leading punctuation' do
+    Slug.for("...hello").should == "hello"
+  end
 
 end