new: dev: added .gitignore

.gitignore

@@ -0,0 +1,15 @@
+# Not sure what a .gitignore is?
+# See: https://git-scm.com/docs/gitignore
+
+# These are directly copied from Jekyll's first-party docs on `.gitignore` files:
+# https://jekyllrb.com/tutorials/using-jekyll-with-bundler/#commit-to-source-control
+
+# Ignore the default location of the built site, and caches and metadata generated by Jekyll
+_site/
+.sass-cache/
+.jekyll-cache/
+.jekyll-metadata
+
+# Ignore folders generated by Bundler
+.bundle/
+vendor/