title: ruby round integer to nearest multiple of 5
body: <p>I want to take an integer and round it up to the next multiple of 5. Like such:</p>
  
  <pre><code>input:    output:
  0    -&gt;   0
  2    -&gt;   5
  3    -&gt;   5
  12   -&gt;   15
  21   -&gt;   25
  30   -&gt;   30
  -2   -&gt;   0
  -5   -&gt;   -5
  etc.
  </code></pre>
  
  <p>My function below accounts for the numbers that are divisible by 10, but I have no idea how to do it for the numbers divisible by 5. This is what I have so far;</p>
  
  <pre><code>    def round_to_next_5(n)
        if n % 5 == 0
          return n
        else 
          return n.round(-1)
        end
      end
  </code></pre>