I used Autoprefixer as suggested in the answers.
I use gulp to handle this when I write SASS. Here is a guide.
Answers here are suggesting to use a prefixed property before the non prefixed one. I agree with a small correction.
.container {
display: -webkit-flex;
-webkit-flex-wrap: wrap;
display: flex;
flex-wrap: wrap;
}
Ideally, you need to list all of the prefixed properties before you start using the non prefixed ones. @Michael_B answer is not perfect in my opinion.
I hope people will find this useful.