code: public ApiKey generateApiKey() {
          URI uri = new URIBase(getBaseUri()).path("_api").path("v2").path("api_keys").build();
          InputStream response = couchDbClient.post(uri, null);
          return getResponse(response, ApiKey.class, getGson());
      }
docs: Use the authorization feature to generate new API keys to access your data. An API key is
  similar to a username/password pair for granting others access to your data.
  <P>Example usage:
  </P>
  <pre>
  {@code
  ApiKey key = client.generateApiKey();
  System.out.println(key);
  }
  </pre>
  <P> Example output:
  </P>
  <pre>
  {@code key: isdaingialkyciffestontsk password: XQiDHmwnkUu4tknHIjjs2P64}
  </pre>
  
  @return the generated key and password
  @see Database#setPermissions(String, EnumSet)