Add git diff support for sops files

.gitattributes

@@ -0,0 +1,6 @@
+secrets/**/*.env    diff=sopsdiffer
+secrets/**/*.env.*  diff=sopsdiffer
+secrets/**/*.ini    diff=sopsdiffer
+secrets/**/*.json   diff=sopsdiffer
+secrets/**/*.yaml   diff=sopsdiffer
+secrets/**/*.yml    diff=sopsdiffer

.gitconfig

@@ -0,0 +1,2 @@
+[diff "sopsdiffer"]
+    textconv = "sops --decrypt"

README.md

@@ -1,3 +1,9 @@
 # NixOSConfig
 
 NixOS Configurations for personal Machines
+
+Run the following command for adding `git diff` support for `sops` in this repository:
+
+```sh
+git config --local include.path ../.gitconfig
+```