code: function upToString() {
              var upStr = '',
                  ctr = 0,
                  items = getActions(build.up),
                  tab,
                  suffix;
              // build the output string for up.
              _.forEach(items, function (v,k) {
                  _.forEach(v, function(item, key){
                      suffix = (ctr < v.length -1) || (k+1 < items.length) ? '\n' : '';
                      tab = ctr > 0 ? getTabs(0, true) : '';
                      upStr += (tab + item + suffix);
                      ctr += 1;
                  });
              });
              return upStr;
          }
docs: Concats all up migration events to string.
  @private
  @memberof Compare
  @returns {string}