add git bisect run script

scripts/bisect.sh

@@ -0,0 +1,20 @@
+#!/bin/sh
+
+# How to use:
+# 1) find a commit that is working fine.
+# 2) Create an integration test capturing the fact that it works (Don't commit it). See https://github.com/jesseduffield/lazygit/blob/master/docs/Integration_Tests.md
+# 3) checkout the commit that's known to be failing
+# 4) run this script supplying the commit sha / tag name that works and the name of the newly created test
+
+# usage: scripts/bisect.sh <ref that works> <integration test name>
+# e.g.   scripts/bisect.sh v0.32.1 mergeConflictsResolvedExternally
+# It's assumed that the current commit (i.e. HEAD) is broken.
+
+set -o pipefail
+
+echo $1
+echo $2
+
+git bisect start HEAD $1
+git bisect run go test ./pkg/gui -run /$2
+git bisect reset