Migration Guide

[effigies]

It would be good to start work on a migration guide for Nipype 1 users to Pydra.

Some ideas for sections:

• How to rewrite your existing interface as a Pydra task
  • Converting input_specs of various styles
  • Converting output_specs
  • How to replace gen_filename and similar
  • Metadata equivalents (argstr, etc.)
• How to rewrite your workflow as a Pydra workflow
  • Replacing Inputnode/outputnode with workflow function parameters/return values
  • Connect statements -> assignment
  • MapNodes -> split/combine
  • iterables -> split
  • JoinNodes -> combine

I would suggest organizing it as:

• migration_guides/
  • nipype_1

This would leave room for guides for users of other workflow engines.

[tclose]

This could be included in the how-to section of the docs

[tclose]

Related to #808

[tclose]

Feel free to dump ideas into this issue