Truncate transaction paths to 70 characters

This ensures that long URLs don't completely mess up the layout of the
table.

app/views/sherlock/transactions/index.html.haml

@@ -27,7 +27,9 @@
         - @transactions.each do |trans|
           %tr
             %td= trans.type
-            %td= trans.path
+            %td
+              %span{title: trans.path}
+                = truncate(trans.path, length: 70)
             %td
               = trans.duration.round(2)
               = t('sherlock.seconds')