Getting change logs between latest and previous tags

ChangeLogs.rb

`git fetch --tags`
tag_name = `git describe --abbrev=0`.split("\n")[0]
current_tag= tag_name.gsub(".","").to_i
tags_dictionary = Hash[`git tag`.split("\n").map{|tag| [tag.gsub(".","").to_i, tag]}] 
tags = `git tag`.split("\n").collect{|tag| tag.gsub(".","").to_i} 
tags.sort

tagIndex= tags.index(current_tag)
previous_tag=tags[tagIndex-1]

change_logs= `git log #{tags_dictionary[previous_tag]}..#{tag_name} --format=%s`.split("\n")
puts change_logs