Added node_modules folder to gitignore

Description

Fixes issue where node_modules folder was not included in . #gitignore file

Docker containers still come up. node_modules folder disappeared from pending changes in git.

Please check [x] all that apply.

[x] My code follows similar styling to existing code in this project
[x ] I have performed a self-review of my own code
[x] I have commented my code, at the very least in hard-to-understand areas
[x] I have made corresponding changes to documentation / READMEs
[x] My changes generate no new warnings
[x] I have remade my frontend and backend Docker containers to ensure my changes do not break the setup for these
[x] I have added tests that prove my fix is effective or that my feature works
[x] New and existing unit tests pass locally with my changes
[x] I have checked my code and corrected any misspellings