Update the plugins managment. Add the function 'omz-plugin' (inspired from bash-it)

plugins/available/themes/themes.plugin.zsh

@@ -0,0 +1,24 @@
+function theme
+{
+    if [ -z "$1" ] || [ "$1" = "random" ]; then
+	themes=($ZSH/themes/*zsh-theme)
+	N=${#themes[@]}
+	((N=(RANDOM%N)+1))
+	RANDOM_THEME=${themes[$N]}
+	source "$RANDOM_THEME"
+	echo "[oh-my-zsh] Random theme '$RANDOM_THEME' loaded..."
+    else
+	if [ -f "$ZSH_CUSTOM/$1.zsh-theme" ]
+	then
+	    source "$ZSH_CUSTOM/$1.zsh-theme"
+	else
+	    source "$ZSH/themes/$1.zsh-theme"
+	fi
+    fi
+}
+
+function lstheme
+{
+    cd $ZSH/themes
+    ls *zsh-theme | sed 's,\.zsh-theme$,,'
+}