The American Bankers Association filed a lawsuit against the National Credit Union Administration in an effort to overturn a rule that makes it easier to join a credit union – rule scheduled to take effect in February next year. Locally, credit unions in the state have seen significant growth in membership and deposits, and the new rule, which allows federal credit unions to apply to serve what are defined as “rural districts” — areas of of up to 1 million people — in addition to areas that…