zsh: show git branch in prompt

.config/zsh/.zshrc

@@ -1,6 +1,16 @@
-# Enable colors and change prompt:
+git_prompt() {
+    local branch="$(git symbolic-ref HEAD 2> /dev/null | cut -d'/' -f3-)"
+    local branch_truncated="${branch:0:30}"
+    if (( ${#branch} > ${#branch_truncated} )); then
+        branch="${branch_truncated}..."
+    fi
+
+    [ -n "${branch}" ] && echo " (${branch})"
+}
+
+setopt PROMPT_SUBST
 autoload -U colors && colors	# Load colors
-PROMPT='%1~%f%b $ '
+PROMPT='%1~%f%b%F{blue}$(git_prompt)%f $ '
 
 # gpg key for ssh authentication
 export SSH_AUTH_SOCK="$(gpgconf --list-dirs agent-ssh-socket)"