Added initial zsh completion support to git_index

zsh now completes all arguments and all directories inside $GIT_REPO_DIR. This is till buggy because not all directories in $GIT_REPO_DIR are actual git projects. Next update will include completing the list in the .git_index file.

lib/git/aliases.sh

@@ -146,5 +146,7 @@ if [ $shell = "bash" ]; then
   # If you know how to rewrite _git_index_tab_completion() for zsh, please send me a pull request!
   complete -o nospace -F _git_index_tab_completion git_index
   complete -o nospace -F _git_index_tab_completion $git_index_alias
+else
+  compdef _git_index_tab_completion git_index $git_index_alias
 fi
 

lib/git/repo_index.sh

@@ -281,6 +281,7 @@ function _git_index_batch_cmd() {
 }
 
 
+if [ $shell = 'bash' ]; then
 	# Bash tab completion function for git_index()
 	function _git_index_tab_completion() {
 		_check_git_index
@@ -317,4 +318,29 @@ function _git_index_tab_completion() {
 		IFS=$' \t\n'
 		return 0
 	}
+else
+	function _git_index_tab_completion() {
+		typeset -A opt_args
 
+		_arguments \
+			"--rebuild[Rebuild repository index]" \
+			"--update-all[Update all indexed repositories]" \
+			"--update-all-with-notifications[Update all indexed repositories with notifications]" \
+			"--list[List all repositories currently present in the index]" \
+			"--count-by-host[Count all repositories per host]" \
+			"--batch-cmd+[Run a git command on all repositories]:git command:->git_command" \
+			":Project name:->projects" \
+			&& return 0
+
+
+		case "$state" in
+			projects)
+				_files -/ -W $GIT_REPO_DIR
+				;;
+			git_command)
+				;;
+		esac
+
+		return 1;
+	}
+fi