title: Clojure swap atom with map values
body: <p>I want to <code>assoc</code>iate values of a map into an <code>atom</code>.
  I could do it like :</p>
  
  <pre><code>  (defonce config (atom {}))
    (swap! config assoc :a "Aaa")
    (swap! config assoc :b "Bbb")
  </code></pre>
  
  <p>But it is repetitive, and makes several calls to <code>swap!</code>.
  I would like to do something like that :</p>
  
  <pre><code>(swap! config assoc  {:a "Aaa"
                        :b "Bbb"})
  ;; this doesn't work :
  ;; Exception in thread "main" clojure.lang.ArityException: Wrong number of args (2) passed to: core$assoc
  </code></pre>
  
  <p>How do I do that ?</p>