Add Dockerfile

I added this so that I could run a nak bunker on my server alongside my other containers. Thought it might be useful for others.

.dockerignore

@@ -0,0 +1,36 @@
+# git files
+.git
+.gitignore
+
+# documentation
+README.md
+LICENSE
+
+# development files
+justfile
+*.md
+
+# test files
+*_test.go
+cli_test.go
+
+# build artifacts
+nak
+*.exe
+mnt
+
+# ide and editor files
+.vscode
+.idea
+*.swp
+*.swo
+*~
+
+# os generated files
+.DS_Store
+.DS_Store?
+._*
+.Spotlight-V100
+.Trashes
+ehthumbs.db
+Thumbs.db