Extract Van Gogh paintings

[Marryweb]

Summary

This PR adds the functionality to extract Van Gogh paintings data from the HTML file.

Changes

• Developed a Ruby script to parse the provided HTML file directly without requiring external HTTP requests.
• Extracted following fields for each painting:
  • Name
  • Extensions
  • Google link
  • Thumbnail image
• Generated clean JSON output van-gogh-paintings-extracted.json.
• Added RSpec tests to validate:
  • Extraction accuracy against an expected dataset.
  • Handling of empty extension fields.
  • Presence and formatting of all required fields.