Add script to run integration tests

scripts/run_integration_tests.sh

@@ -0,0 +1,20 @@
+#!/bin/sh
+
+# This is ugly, but older versions of git don't support the GIT_CONFIG_GLOBAL
+# env var; the only way to run tests for these old versions is to copy our test
+# config file to the actual global location. Move an existing file out of the
+# way so that we can restore it at the end.
+if test -f ~/.gitconfig; then
+  mv ~/.gitconfig ~/.gitconfig.lazygit.bak
+fi
+
+cp test/global_git_config ~/.gitconfig
+
+go test pkg/integration/clients/*.go
+EXITCODE=$?
+
+if test -f ~/.gitconfig.lazygit.bak; then
+  mv ~/.gitconfig.lazygit.bak ~/.gitconfig
+fi
+
+exit $EXITCODE