add gitignore

.gitignore

-# Conda environment
-*-env
-
-# Xaringan-related files
-**/*_files
-
-# Lecture-related files
-lectures/**/*.html
-# lectures/**/*.pdf
-lectures/*/*/remark-css-0.0.1/default.css
-lectures/*/*/header-attrs-2.3/header-attrs.js
-
 # Various
-.snakemake
 .DS_Store
-
-# Output files from running tutorials
-jupyter/report.html
-jupyter/summary.txt
-jupyter/.ipynb_checkpoints
-**/data
-**/intermediate
-**/results
-**/work
-rmarkdown/.R*
-rmarkdown/*html
-rmarkdown/*Rproj
-snakemake/*txt
-snakemake/*png
-snakemake/*tsv
-.Rproj.user
-
-#compiled site
-site