function addIgnoreFromFile(input) {
  let lines = [];
  let files = [];
  if (input) {
    files = files.concat(input);
  }

  files.forEach(function(config) {
    const stats = fs.statSync(config);
    if (stats.isFile()) {
      const content = fs.readFileSync(config, 'utf8');
      lines = lines.concat(content.split(/\r?\n/));
    }
  });

  lines.forEach(addIgnorePattern);
}
Adds ignore patterns by reading files
@param {String|Array<String>} input - the paths to the ignore config files