fix #108

* implement selectRow.bgColor

* add story for selectRow.bgColor

* add testing for selectRow.bgColor

* patch docs for selectRow.bgColor

docs/row-selection.md

@@ -11,6 +11,7 @@ The following are available properties in `selectRow`:
 * [mode (**required**)](#mode)
 * [style](#style)
 * [classes)](#classes)
+* [bgColor](#bgColor)
 * [nonSelectable)](#nonSelectable)
 
 #### Optional
@@ -88,6 +89,27 @@ const selectRow = {
 };
 ```
 
+## <a name='bgColor'>selectRow.bgColor - [String | Function]</a>
+The backgroud color when row is selected
+
+```js
+const selectRow = {
+  mode: 'checkbox',
+  bgColor: 'red'
+};
+```
+
+There's also a more good way to custom it:
+
+```js
+const selectRow = {
+  mode: 'checkbox',
+  bgColor: (row, rowIndex) => {
+    return ....;  // return a color code
+  }
+};
+```
+
 ## <a name='nonSelectable'>selectRow.nonSelectable - [Array]</a>
 This prop allow you to restrict some rows which can not be selected by user. `selectRow.nonSelectable` accept an rowkeys array.