Bootstrap buttons overriding with sass each.

each.scss

$buttons: (
  info: blue,
  success: green,
  warning: yellow,
  danger: red
);

.btn{
  @each $btn-type, $btn-colour in $buttons {
    &.btn-#{$btn-type} {
      background-color: #{$btn-colour};
      border-color: #{$btn-colour};
      color: #fff;
    }
  }
}