DEV: prints timestamp at every docker:test commands (#7628)

lib/tasks/docker.rake

@@ -32,6 +32,7 @@
 #       docker run -e SKIP_CORE=1 SINGLE_PLUGIN='my-awesome-plugin' -v $(pwd)/my-awesome-plugin:/var/www/discourse/plugins/my-awesome-plugin discourse/discourse_test:release
 
 def run_or_fail(command)
+  log(command)
   pid = Process.spawn(command)
   Process.wait(pid)
   $?.exitstatus == 0
@@ -47,6 +48,10 @@ def run_or_fail_prettier(*patterns)
   end
 end
 
+def log(msg)
+  STDERR.puts "#{Time.now.iso8601}: #{msg}"
+end
+
 desc 'Run all tests (JS and code in a standalone environment)'
 task 'docker:test' do
   begin