Update README.md
When generating SQL from a diff, ->columns is not available, but ->to->columns is
Merge pull request #287 from iarna/truncate-substitute-fixes

When generating SQL from a diff, ->columns is not available, but ->to->columns is
Release Modyllic-v0.2.31
Release Modyllic-0.2.31
Merge branch 'upstream-wiki'
Release Modyllic-0.2.31