title: Read vector of strings value from JSON file, in C++ using Boost
body: <p>I am new to Boost and Json.
  It should be very simple, but I can't find the answer.</p>
  
  <p>How do I read a value that is vector of strings in C++ using Boost.</p>
  
  <p>Content of Json file for example :</p>
  
  <pre><code>{  
  "keyword1": ["string1", "string2"],  
  "keyword2": ["string3", "string4"] 
  }
  </code></pre>
  
  <p>Finally I would like to have vector for each keyword:</p>
  
  <pre><code>vector&lt;string&gt; keyword1;
  vector&lt;string&gt; keyword2;
  </code></pre>