code: function writeJSON(dbName, schema) {
  
      var baseUrl = 'http://www.filltext.com/?',
          promises = [],
          collection;
  
      for (collection in schema) {
  
          var meta = schema[collection].meta,
              fields = meta.fields,
              url;
  
          url = Object.keys(fields).map(function(key) {
              if (fields[key][0] === '[' && fields[key].slice(-1) === ']') {
                  return key + '=' + fields[key];
              }
              return key + '={' + fields[key] + '}';
          }).join('&') + '&rows=' + meta.rows;
  
          console.log('Url for', collection, url);
  
          (function(c) {
              promises.push(fetch(baseUrl + url).then(function(response) {
                  return response.json();
              })
              .then(function(rows) {
                  schema[c] = rows;
              }));
          })(collection);
      }
  
      return Promise.all(promises).then(function() {
          fs.writeFile(dbName, JSON.stringify(schema, null, 4), function(err) {
              if (err) {
                  Promise.reject('Failed to save JSON file: ' + err);
              }
          });
      });
  }
docs: Writes generated JSON into file.
  @param dbName {String} Name of the file to create.
  @param schema {Object} Populated object of collections.
  @return {Promise}