Ruby 2.1.0 #major version, minor version and the patch level; Rails 4.1.0
##Semantic versioning Left most number is the version number, this is the particular version, brand new version, if you wanna use with old code you need to read documentation; Rails 4.2.0 Rails 4.3.5 #Stuff that has the same major version number is all compatible with each other;
##Tags Let you put a specific name to a particular version; A release is a particular kind of tag #Lets you add some documentation, make it downloadable as a zip file; jQuery, releases, you also create a zipFile, people that know nothing about git can just download the zip file; You can tag a release, a special version of a commit that has a name and special information;