v2.0.0

BREAKING CHANGE: option modelPath is renamed to model

📚 PR:

• Add support for passing the model programmatically
• Improve comment
• Simplify implementation, add test
• Remove unnecessary change
• Fix readme
• Move external import
• Merge pull request #3 from kibertoad/feature/support-model
• Make adapter optional to support in-memory cases
• Merge pull request #5 from kibertoad/feature/optional-adapter