Add containerStyle prop to readme

README.md

@@ -99,6 +99,7 @@ component as the back of the card.
 | Props                | Type   | Description                                                                                                                 | Default      |
 | -------------------- | ------ | --------------------------------------------------------------------------------------------------------------------------- | ------------ |
 | cardZIndex           | string | z-Index for the flip card. Used to help solve context stack issues while using multiple flip cards.                         | auto         |
+| containerStyle       | object | Extra css styling that can be applied to the container.                                                                     | {}           |
 | isFlipped            | bool   | False to show the front of the card, true to show the back                                                                  | undefined    |
 | flipSpeedBackToFront | number | The speed of the flip animation when the card flips from back to front, the higher the number the slower the flip animation | 0.6          |
 | flipSpeedFrontToBack | number | The speed of the flip animation when the card flips from front to back, the higher the number the slower the flip animation | 0.6          |

src/ReactCardFlip.jsx

@@ -118,6 +118,7 @@ ReactCardFlip.propTypes = {
       return new Error(`${componentName} requires two children.`);
     }
   },
+  containerStyle: PropTypes.object,
   flipDirection: (props, propName, componentName) => {
     if (!props[propName]) {
       return;