plug(RateLimiter, [name: :authentication] when action in [:user_exists, :check_password])
plug(RateLimiter, [name: :authentication, params: ["user"]] when action == :check_password)
def user_exists(conn, %{"user" => username}) do
plug(RateLimiter, [name: :authentication] when action in [:user_exists, :check_password])
plug(RateLimiter, [name: :authentication, params: ["user"]] when action == :check_password)
def user_exists(conn, %{"user" => username}) do