title: How to make a "patternProperty" required in JSON Schema (Ruby)
body: <p>Consider the following JSON :</p>
  
  <pre><code> {
        "1234abcd" : {
                       "model" : "civic"
                        "made" : "toyota"
                        "year" : "2014"
                       }
  
   }
  </code></pre>
  
  <p>consider another JSON : </p>
  
  <pre><code> {
        "efgh56789" : {
                       "model" : "civic"
                        "made" : "toyota"
                        "year" : "2014"
                       }
  
   }
  </code></pre>
  
  <p>the outermost alphanumeric key will vary and required, if the key was fixed; let's say "identifier" then the schema was straightforward, however since the key-name is variable, we have to use <code>patternProperties</code>, how can I come up with a schema that captures these requirement for the outermost key: </p>
  
  <ol>
  <li>property name (key) is variable</li>
  <li>required</li>
  <li>alphanumeric lowercase</li>
  </ol>
  
  <p>using json-schema : <a href="https://github.com/ruby-json-schema/json-schema" rel="noreferrer">https://github.com/ruby-json-schema/json-schema</a> in ruby.</p>