Updated Container API (markdown)

Container-API.md

@@ -141,6 +141,36 @@ if err != nil {
 The following options can be used to align a widget within the container both
 horizontally and vertically.
 
+[[/images/container-api/aligned_button.gif|aligned_button]]
+
+The following code aligns the button widget into the top right corner as shown above:
+
+```go
+tb, err := termbox.New()
+if err != nil {
+    panic(err)
+}
+defer tb.Close()
+
+b, err := button.New("hello world", func() error {
+    return nil
+},
+)
+if err != nil {
+    return err
+}
+
+c, err := container.New(
+    t,
+    container.PlaceWidget(b),
+    container.AlignHorizontal(align.HorizontalRight),
+    container.AlignVertical(align.VerticalTop),
+)
+if err != nil {
+    return err
+}
+```
+
 #### [container.AlignHorizontal](https://godoc.org/github.com/mum4k/termdash/container#AlignHorizontal)
 
 The **container.AlignHorizontal** option is used to specify horizontal alignment for the widget. Refer to the [[Align API|align-api]] for alignment options.