Add a way to create a traceability report.

[jacebrowning]

@theovoss @robertberrington How about:

$ doorstop trace LLR123
LLT123:
    child_links:
    - LLT001
    - LLT002
    parent_links:
    - HLR001
    - HLR002

$ doorstop trace LLR
LLR001:
    child_links:
    - LLT001
    - LLT002
    parent_links:
    - HLR001
    - HLR002
...
LLR999:
    child_links:
    - LLT004
    parent_links: []

$ doorstop trace all
SYS001:
...
SYS999:
...
HLR001:
...
LLR001:
...
LLR999:
...

$ doorstop trace all path/to/report.xlsx

File output would be in the format of: https://github.com/jacebrowning/doorstop/pull/20#issuecomment-45218149

Perhaps file output is all that's really needed?

[robertberrington]

@jacebrowning I like it! I think the command line and file options are both good. I'd like to construct the requirements/tree in doorstop, then maybe interactively inspect tracing at the command line.

[asimon-1]

I authored a tool to perform a similar task - essentially listing requirements and the items that claim them as parent links. This could easily be incorporated into Doorstop natively. The tool isn't very complex since my use-case was relatively simple, but more complex trees could be handled without too much additional effort.

https://github.com/asimon-1/rtm_doorstop