chore: add flake

Signed-off-by: Nikolaos Karaolidis <nick@karaolidis.com>

.gitignore

@@ -16,3 +16,13 @@ target/
 #  and can be added to the global gitignore or merged into this file.  For a more nuclear
 #  option (not recommended) you can uncomment the following to ignore the entire idea folder.
 #.idea/
+
+# ---> Nix
+# Ignore build outputs from performing a nix-build or `nix build` command
+result
+result-*
+
+# Ignore automatically generated direnv output
+.direnv
+
+.cargo/