Measurable ratings: replacement ratings

[davidwatkins73]

Idea is to allow capture of rating transitions within an app. For example App A uses WebSphere as a technology product and wants to express that they will be moving to Spring Boot in a future release. By using the rating tree (and following a similar pattern to app/fn decomms and replacements) the user could search for replacement taxonomy items.

To help user select an appropriate rating scheme item, we should add an optional assessment rating which gives a default value.

• [ ] Add default rating to measurables (i.e. Spring Boot is 'invest') (see that #5157 is done first).
  • [ ] add new column to category to point to the assessment def id.
  • [ ] show assessment defn's on measurable page
• [ ] Add table for capturing replacement ratings (need measurable_id, takeover_date and rating + comment ?)
• [ ] UI stuff (needs to gracefully handle ratings if no default rating is known)
  • [ ] Edit screens
  • [ ] View modifications (what to use as an icon ? - hands are already used for app decomms)
• [ ] Bonus: nice looping arcs between tree items to show transitions
• [ ] Bonus: suggested replacements (perhaps stat driven ?)

One concern is that this only makes sense for certain taxonomies. For example a functional taxonomy is unlikely to benefit from this ability. Therefore:

• [ ] add is_decommissionable and is_replaceable_by_app columns to measurable category (pls think of better names!)
  • [ ] these toggles will enable/disable parts of the rating ui, hopefully reducing complexity for end users.