Docker bugfix

[giannou]

Please fill following information
(Add additional info if you think its important and not covered by this Pull Request (PR)):

Purpose of this PR

• Fix an error in the usage of Docker in the README file

Performance loss/gain from current default behavior

• Add an image using plot from shinyresults::appResults() and annotate accordingly.

• %performance loss/gain = 100*Runtime from PR/Runtime from current default from develop branch.

Type of change

• Bug fix (Change which fixes an issue).
• New feature (Change which adds functionality).
• Minor change (Change which does not modify core model code i.e., in /modules).
• Major change (fix or feature that would change current model behavior).

How Has This Been Tested?

• Runs using starting script which tests current defaults (using test_runs.R).
• Runs using starting script which successfully runs the same scenarios as in test_runs.R but with the changes from PR.
• (If applicable) Runs using different scenarios/mappings which are not the default (12 regions/c200 clusters).

Additions or Changes to default configuration (default.cfg):

Additions are the introduction of new model components in default config

Changes are deletion or updates to the existing model components in default config

• Realizations:
• Scenario switches:
• Scalars/Constants:
• Model interfaces:
• Others:

Checklist:

• Self-review of my own code.
• Added changes to CHANGELOG.md
• No hard coded numbers and cluster/country/region names.
• The code doesn't contain declared but unused parameters or variables.
• In-code comments added including documentation comments.
• Compiled and checked resulting documentation with goxygen::goxygen() for the new/updated parts.
• Changes to magpie4 R library for post processing of model output (ideally backward compatible).

Special comments/warnings

• Notes