code: public Javalin routes(@NotNull EndpointGroup endpointGroup) {
          ApiBuilder.setStaticJavalin(this);
          endpointGroup.addEndpoints();
          ApiBuilder.clearStaticJavalin();
          return this;
      }
docs: Creates a temporary static instance in the scope of the endpointGroup.
  Allows you to call get(handler), post(handler), etc. without without using the instance prefix.
  
  @see <a href="https://javalin.io/documentation#handler-groups">Handler groups in documentation</a>
  @see ApiBuilder