docs: function replaceVariables(localPath, variables) {
      return new Promise(function(resolve, reject) {
          // Read the file
          let body = fs.readFileSync(localPath, 'utf8');
  
          // Do the replacement for all of the variables
          const keys = Object.keys(variables);
          keys.forEach(function(key) {
              const value = variables[key];
              const re = new RegExp(`"\\$${key}"`, 'g');
  
              // Parse the value (to see if it is falsey)
              try {
                  const parsed = JSON.parse(value);
                  body = body.replace(re, parsed ? `"${parsed}"` : `null`);
              } catch (err) {
                  // Not valid JSON, treat it as a string
                  body = body.replace(re, `"${value}"`);
              }
          });
  
          console.log('Variables replaced', body);
          fs.writeFile(localPath, body, function(err) {
              if (err) return reject(err);
              resolve(localPath);
          });
      });
  }