code: function _moveFastBootInitializers(project, rootPath) {
  
    // check to see if it is a fastboot complaint addon
    const isFastbootAddon = _checkInitializerTypeExists(rootPath, 'fastboot');
    if (isFastbootAddon) {
      project.ui.writeDeprecateLine(`Having fastboot specific code in app directory of ${rootPath} is deprecated. Please move it to fastboot/app directory.`);
  
      const fastbootDirPath = path.join(rootPath, FASTBOOT_DIR);
      // check if fastboot/app exists
      if (!existsSync(fastbootDirPath)) {
        fs.mkdirsSync(fastbootDirPath);
      }
  
      // copy over app/initializers/fastboot and app/instance/initializers/fastboot
      fastbootInitializerTypes.forEach((fastbootInitializerType) => {
        const srcFastbootPath = path.join(rootPath, 'app', fastbootInitializerType, 'fastboot');
  
        if (existsSync(srcFastbootPath)) {
          const destFastbootPath = path.join(fastbootDirPath, fastbootInitializerType);
          if (!existsSync(destFastbootPath)) {
            fs.mkdirSync(destFastbootPath);
          }
  
          // fastboot initializer type exists so we need to move this fastboot/app
          const fastbootFiles = fs.readdirSync(srcFastbootPath);
          fastbootFiles.forEach((fastbootFile) => {
            const srcPath = path.join(srcFastbootPath, fastbootFile);
            const destPath = path.join(destFastbootPath, fastbootFile);
            fs.copySync(srcPath, destPath);
  
            // delete the original path files so that there are no two initializers with the same name
            fs.unlinkSync(srcPath);
          });
        }
      });
    }
  }
docs: Function to move the fastboot initializers to fastboot/app
  @param {Object} project
  @param {String} rootPath