add custom "labels" or words signed to images

[Unacceptium]

-feature request- i would like to sign an image by hand with a word, so the searches can be improved and the app would be more universal.

--reason-- i got images about crane trucks and mining trains with overhead wires. if theres a feature like that, i can make the mining train dont appear when i search crane. or adding brands assigned to images... etc etc

--extra-- i don't know if theres an feature in new versions. i needed to use a fork for storage permissions. (#17)