Closing and re-opening a pull request causes double/triple commenting.

[groovecoder]

STR:

1. Create a PR with the hook enabled
2. Close the PR
3. Re-open the PR

Expected results:
Only opening a PR should add a comment

Actual results:
Closing the PR created another batch of line-by-line comments

Example:
groovecoder/discord-test#1

[openjck]

Thanks for the detailed STR! This might be related to #79.

[Faeranne]

opening and creating a PR both initiate the same API Action. We need to be tracking comments to fix this properly. I assume fixing #79 should make this issue go away, even though they are technically different issues. Going to leave this issue open in-case the fix is not enough.

[groovecoder]

@openjck and I thought a solution may be:

1. Create a comments table in our shiny new postgres database
2. Update the comment code to store a hash of the url, file name, line number, and line contents
3. Before making a comment, make sure there isn't already a comment record with the same hash

That file name, line number, and line contents combination seems to be the same keys that GitHub uses to decide whether to collapse comments in the PR interface. But we can tweak the hash components as needed.

[openjck]

It sounds like this issue and #79 share the same underlying cause. We should never post the same comment twice. I'll update the language of #79 to be more general and call this a duplicate.