Fix condition

Author: crbelaus

lib/error_tracker.ex

@@ -112,7 +112,7 @@ defmodule ErrorTracker do
 
     ignorer = Application.get_env(:error_tracker, :ignorer)
 
-    if ignorer && !ignorer.ignore?(error, context) do
+    if is_nil(ignorer) || !ignorer.ignore?(error, context) do
       {_error, occurrence} = upsert_error!(error, stacktrace, context, reason)
       occurrence
     end