sha,message,author_date,committer_date,raw_author,raw_author_label,raw_committer,raw_committer_label,repo,repo_label,author,author_label,committer,committer_label
dbbe707841973b50a76d2703003ae2c40e7ad1fd,"publish_subcommand hook + default plugins mechanism, used for publish heroku/now (#349)

This change introduces a new plugin hook, publish_subcommand, which can be
used to implement new subcommands for the ""datasette publish"" command family.

I've used this new hook to refactor out the ""publish now"" and ""publish heroku""
implementations into separate modules. I've also added unit tests for these
two publishers, mocking the subprocess.call and subprocess.check_output
functions.

As part of this, I introduced a mechanism for loading default plugins. These
are defined in the new ""default_plugins"" list inside datasette/app.py

Closes #217 (Plugin support for datasette publish)
Closes #348 (Unit tests for ""datasette publish"")
Refs #14, #59, #102, #103, #146, #236, #347",2018-07-26T05:15:59Z,2018-07-26T05:15:59Z,2946d096d0cdefdc017559e6b57e87658736e843,Simon Willison,cd792325681cbad9f663f2879d8b69f1edbb678f,GitHub,107914493,datasette,9599,simonw,19864447,web-flow