+=) operator.
Example:
```js
var anAdjective = "awesome!";
var ourStr = "freeCodeCamp is ";
ourStr += anAdjective;
// ourStr is now "freeCodeCamp is awesome!"
```
someAdjective and append it to myStr using the += operator.
someAdjective should be set to a string at least 3 characters long.
    testString: assert(typeof someAdjective !== 'undefined' && someAdjective.length > 2);
  - text: You should append someAdjective to myStr using the += operator.
    testString: assert(code.match(/myStr\s*\+=\s*someAdjective\s*/).length > 0);
```