static configureOptions(commandName, yargs, extensions, onlyOptions) {
        each(this.options || {}, (option, optionName) => {
            yargs = yargs.option(kebabCase(optionName), option);
        });

        if (onlyOptions) {
            return yargs;
        }

        if (this.longDescription) {
            yargs.usage(this.longDescription);
        }

        yargs.epilogue('For more information, see our docs at https://ghost.org/docs/ghost-cli/');

        return yargs;
    }
Configure Yargs for this command. Subclasses can override this to do anything
specific that they need to do at config time

@param {String} commandName Name of the command
@param {Yargs} yargs Yargs instance
@param {Array} extensions Array of discovered extensions
@return {Yargs} Yargs instance after options are configured

@static
@method configureOptions
@public