Consider making adapter classes for each service to convert JSON into vertical model objects

I.e.,

```python
# adapters/tumblr_adapter.py

class TumblrAdapter:
    def adapt_social_posting_vertical(...):
        ...

# tumblr.py

class TumblrTransferService:
    adapter = TumblrAdapter()

    ...

    def fetch_social_posting_vertical(...):
        ...
        return self.adapter.adapt_social_posting_vertical(...)
```