A tutorial for adding an upper bound on investment

[behnam-zakeri]

This PR is to demonstrate how GAMS files can be changed for adding a new variable or parameter. This was part of the hands-on session of the MESSAGEix Community meeting 2022.

Notice: This PR does not need to be merged, because the changes made in the GAMS file here are intended to be only for demonstration.

How to review

Switch to this branch and run the accompanying tutorial. It should run and solve successfully (no errors and unfeasibility, otherwise stated in the tutorial). Please make sure the text in the tutorial is clear and understandable.

PR checklist

• Continuous integration checks all ✅
• Add or expand tests; coverage checks both ✅ (the tutorial is being tested in test_tutorials.py)
• Add, expand, or update documentation. (the tutorial should have the required documentation).
• Update release notes.

[khaeru]

Thanks for this contribution! FYI, you can:

• Click on the top right where it says "Still in progress? Convert to draft"
• Remove the text "[WIP] " from the title.

The draft status conveys clearly that this is work in progress.

Please also:

• Assign yourself and anyone else who will complete the PR.
• Add it to "MESSAGEix team" under "Projects".

[codecov]

Codecov Report

Merging #602 (5f1bb83) into main (3b6651f) will not change coverage.
The diff coverage is n/a.

@@          Coverage Diff          @@
##            main    #602   +/-   ##
=====================================
  Coverage   93.5%   93.5%           
=====================================
  Files         44      44           
  Lines       3511    3511           
=====================================
  Hits        3283    3283           
  Misses       228     228           

Impacted Files	Coverage Δ
message_ix/message_ix/models.py	98.2% <0.0%> (ø)
message_ix/message_ix/tests/test_tutorials.py	100.0% <0.0%> (ø)