Add topological sorting for dumped views using TSort

[msorc]

This introduces topological sorting (https://ruby-doc.org/stdlib-2.6.8/libdoc/tsort/rdoc/TSort.html#method-i-tsort) for views in dumps which will sort views alphabetically and in case of dependencies between views will use a topological sorting.
That provides a consistent views ordering in database dumps and prevents of having occasional diffs in schema dumps.

Based on discussion here #263 and code samples #263 (comment) and #263 (comment)

[msorc]

Not sure how do you deal with the Hound so made a separate commit to satisfy it

[nedcampion]

This is great, thank you @msorc this one saved us a bunch of time. Any thoughts on merging this one @derekprior @calebhearth, as it relates to #263. Anvyl would be happy to help QA a pre-release version.

[Unknown-Guy]

Suggested change

	source_v = relation["source_table"]
	dependent = relation["dependent_view"]
	source_v = "#{relation["source_schema"]}.#{relation["source_table"]}"
	dependent = "#{relation["dependent_schema"]}.#{relation["dependent_view"]}"

Needs schema here in our app otherwise order is wrong.

[Unknown-Guy]

Suggested change

	AND source_table.relkind IN ('m', 'v') AND dependent_view.relkind IN ('m', 'v')
	ORDER BY dependent_view.relname;
	AND source_table.relkind IN ('m', 'v') AND dependent_view.relkind IN ('m', 'v');

Iterating over result does not need this order so this line can be removed.

[gr8bit]

Anyone please merge this to clean up the schema diffs :(

[calebhearth]

I've rebased this in #398 (but would be fine closing that if @msorc hasn't gotten fed up with me and wants to rebase this themselves) and plan to test this out now that I have an app that sees this issue, which I'm very excited about.

[msorc]

No, I don't want to rebase it myself :)
@calebhearth please proceed whichever way to finally merge it.

[Unknown-Guy]

Check my comments above - schema_dumper.rb needs schema on lines 73-74. We are using fork with those changes for almost year without issues.

[derekprior]

superseded by #398