Fix the bug in alignment

Merge pull request #30 from doccano/feature/fix-bug

Fix bug

Add a helper method to pre-processing

Merge pull request #29 from doccano/feature/preprocessing

Add pre-processing helper method

Update document

Merge pull request #27 from doccano/feature/readme

Fix a broken link in README.md

Bug fix

Merge pull request #26 from doccano/feature/bump-version

Bump version

Replace pytokenizatoins with spacy-alignments

Merge pull request #22 from doccano/feature/spacy-alignment

Use spacy-alignments

v0.9.1

Merge pull request #18 from tech-sketch/feature/refine-docs

Refine docs