Added utils/scroll_to.js for animated scroll

https://gist.github.com/andjosh/6764939

app/javascript/gabsocial/utils/scroll_to.js

@@ -0,0 +1,30 @@
+// https://gist.github.com/andjosh/6764939
+export const scrollTo = (element, to, duration) => {
+  var start = element.scrollTop,
+    change = to - start,
+    currentTime = 0,
+    increment = 20
+
+  var animateScroll = function () {
+    currentTime += increment
+    var val = Math.easeInOutQuad(currentTime, start, change, duration)
+    element.scrollTop = val
+    if (currentTime < duration) {
+      setTimeout(animateScroll, increment)
+    }
+  }
+  
+  animateScroll()
+}
+
+
+//t = current time
+//b = start value
+//c = change in value
+//d = duration
+Math.easeInOutQuad = function (t, b, c, d) {
+  t /= d / 2
+  if (t < 1) return c / 2 * t * t + b
+  t--
+  return -c / 2 * (t * (t - 2) - 1) + b
+}