Odd logic for creating new discorse thread for 'need discussion' tag

[Fildrance]

Logic for creating new discorse thread -

SS14.Labeller/SS14.Labeller/Handlers/LabelPullRequestHandler.cs

Line 138 in 5cb5433

if (exists)

is really odd. By code logic it should not work properly, it is basically saying 'create thread if it already exists' but facts prove that currently running version of labeller contains this code and works properly - creates new discorse threads (based on changes from Feb by PJB that changed template for new threads).

This logic is missing tests (LabelPullRequestHandler have not full coverage), so adding new integration test should reveal where the problem lies

[Fildrance]

One core idea of how things could be more clear is adding way for application to report commit it was built upon (through webapi i guess) so we could understand under what code version we operate.