relative timestamps

app/assets/javascripts/ago.js

@@ -0,0 +1,31 @@
+$.fn.ago = function(callback) {
+  units = [
+    ['m', 60],
+    ['h', 3600],
+    ['d', 86400],
+    ['w', 604800],
+    ['y', 31536000]
+  ];
+  this.each(function() {
+    ago_date = callback ? callback(this) : new Date($(this).text());
+    ago_time = Math.floor((new Date().getTime() - ago_date.getTime())/1000);
+    ago_unit = null;
+    units.forEach(function(time, i) {
+      if (Math.abs(ago_time) >= time[1]) {
+        ago_unit = i;
+      } else {
+        // we found the greatest unit
+        return;
+      }
+    });
+
+    if (ago_unit !== null) {
+      unit    = units[ago_unit];
+      ago_str = Math.abs(Math.floor(ago_time/unit[1])).toString() + unit[0] + (ago_time < 0 ? " ahead" : " ago");
+    } else {
+      ago_str = "just now";
+    }
+
+    $(this).text(ago_str);
+  });
+};