Priority for extractors

| Q             | A
| ------------- | ---
| Bug fix?      | no
| New feature?  | yes
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | #107 
| License       | MIT
| Doc PR        | need to be written
you don't need this. just `$extractors[]` is good enough. arrays are ordered, this syntax appends to the end.