Replace gerrit-github-sync with newer gitsync container.
diff --git a/gitsync/ssh_config b/gitsync/ssh_config
new file mode 100644
index 0000000..4db8851
--- /dev/null
+++ b/gitsync/ssh_config
@@ -0,0 +1,5 @@
+Host github.com
+    Hostname github.com
+    User git
+    IdentityFile /home/gitsync/.ssh/id_rsa
+    IdentitiesOnly yes