Ability to Generate Migrations with an Optional Template

[hjc]

Arnold should have a command, such as: arnold generate my_migration_name that generates a base migration file for easy iteration.

My thoughts on this:

• The name of the file becomes: $(date)_${migration_name}, but is customizable through an argument.
• The template used is very generic by default, but specifying a custom template to be used with Jinja is also possible (or Mako, whichever templating language is nicer).
• The custom template has access to some variables such as:
  • current date
  • migration name
  • full migration file name

Right now we have #26 pending, for creating an initial migration for a model, but there's to aid in creating future migrations for models.

[cam-stitt]

I think having a generate command could be of value. The goal of arnold was to be as minimal as possible, so I don't think custom templates will fit in with the mission. Migration files should follow a single pattern.