Added hooks to templates for relationships.

[mmitten]

My attempt to resolve #445

Added into the templates for relationships as I did not see any other place that made sense for how the hooks otherwise behaved. Happy to follow up if a something was missed.

[stephenafamo]

While I see this as a good change, I wonder if this may cause issues for those who are used to the current behaviour 🤔

[mmitten]

Now that you mention it, it could be a breaking change, as adding another hook trigger where it was previously not expected could lead to some unpleasant side effects.

I am not opposed to tabling this for a major version revision, as the use case I wrote it for has since been resolved with something else.

[stephenafamo]

I'll label this as breaking and may add it to an eventual v5 release.