Avoid unnecessary queries when finding or creating tags

[bduran82]

This is an optimisation to avoid database queries when finding or creating a list tags in ActsAsTaggableOn::Tag find_or_create_all_with_like_by_name:

The list of tags to be retrieved is only updated once and refreshed again in case there is a tag name collision.

This solves #838 issue

[thromera]

Very much needed actually.

[jnimety]

I'm running into this performance problem with large numbers of tags too, the patch seems to fix the issue.

[gen0cide]

Any idea when this could be merged into v5?

[toobulkeh]

Would love a merge on this

[bitops]

👍 on this getting merged.

[Cremz]

This really needs to happen.
It's not only when there are many tags, even 5-10 is enough to make everything seems slow.
It makes one query for each tag, each query takes about 2 seconds. ( i have about 130k tags already). it's not efficient at all. I try to add one record, that takes 5 ms, but updating the tags takes up to 10 seconds