Improve git template and add post-chehckout hook to alias master to main

modules/home-manager/git/template.nix

@@ -1,21 +1,40 @@
 { pkgs, config, ... }: {
   programs.git.extraConfig.init.templatedir = "${config.home.homeDirectory}/.git_template";
 
-  home.file.".git_template/hooks/commit-msg".source = pkgs.writeShellScript "commit-msg" ''
-    readonly COMMIT_MSG_FILE="$1"
+  home.file = {
+    ".git_template/hooks/commit-msg".source = pkgs.writeShellScript "commit-msg" ''
+      #!/usr/bin/env bash
 
-    function check_commit_msg_length {
-        readonly MAX_MSG_LENGTH=72
+      readonly COMMIT_MSG_FILE="$1"
 
-        local title=$(head -n 1 "$COMMIT_MSG_FILE")
+      function check_commit_msg_length {
+          readonly MAX_MSG_LENGTH=72
 
-        if [ ''${#title} -gt $MAX_MSG_LENGTH ]; then
-            # TODO figure out how to use hex colors variable
-            echo -e "\x1b[1;38;5;203mCommit title is ''${#title} characters long, must be equal or shorter than $MAX_MSG_LENGTH characters!\e[0m";
-            exit 1
+          local title=$(head -n 1 "$COMMIT_MSG_FILE")
+
+          if [ ''${#title} -gt $MAX_MSG_LENGTH ]; then
+              # TODO figure out how to use hex colors variable
+              echo -e "\x1b[1;38;5;203mCommit title is ''${#title} characters long, must be equal or shorter than $MAX_MSG_LENGTH characters!\e[0m";
+              exit 1
+          fi
+      }
+
+      check_commit_msg_length
+    '';
+
+    ".git_template/hooks/post-checkout".source = pkgs.writeShellScript "post-checkout" ''
+      #!/usr/bin/env bash
+
+      readonly CURRENT_BRANCH="$2"
+
+      if [ "$CURRENT_BRANCH" = "main" ]; then
+        if [ $(git show-ref --verify --quiet refs/heads/master) ]; then
+            git branch -D master
         fi
-    }
 
-    check_commit_msg_length
-  '';
+        git symbolic-ref refs/heads/master refs/heads/main
+        git switch master
+      fi
+    '';
+  };
 }