Add hallmark init command

[vweevers]

Forked from #84 (comment).

@ralphtheninja Should this just create an empty changelog (i.e. # Changelog, that's it), or something more advanced?

[ralphtheninja]

I was thinking it could use the first tag to create the "initial version" which also has a different markdown pointing to the tag instead of the compare diff link.

Alternatively hallmark init [version] could be provided to set the first version.

Another alternative would be to have the whole changelog populated for all versions, e.g. hallmark --init --all, which basically would do hallmark insert for all tagged versions.

[ralphtheninja]

The main reason for this type of change would be to make it easier for people to get started with a changelog in an existing project instead of saying "oh, it would be nice with a changelog" but no one has the energy to start on one if the project has been around for a bit of time.

[vweevers]

In changelogs that I've created recently, I didn't write the full history. Just started at the latest release. Indeed because I didn't have the energy. Even if hallmark init could generate it, I might still skip that, because it's a lot of work to cleanup commit messages. And my primary objective is to communicate changes of new releases going forward.

I like your suggestion of hallmark init [version], because it offers a way of at least documenting recent releases (or however far back you want to go). Older projects may have missing tags, no semver, etc, so it'd be very helpful to specify a non-problematic version to start at. I think I do want hallmark init to do as much work as possible. Meaning, it'll create releases from the specified version until the semver-latest tagged version (if any).

Perhaps, to accommodate different use cases (because you're looking to start at the oldest release, which is admirable 😉) the input to hallmark init should be a range (gte/lte/limit). That way it wouldn't blurt out a massive changelog forcing you to cleanup all releases in one go. I don't want to overcomplicate the options though.

[vweevers]

4.1.0