Using a licence will clearly define how you want your content to be shared. It’s a good idea to share using a licence so that other know in which ways they can use your code. For example if you don’t want your code to be used commercially, you can choose a licence that specifies this.
There are many to choose from and it needs to take account of the agreement you have with your employer to share your work.
http://choosealicense.com/ A useful guide on the basic options for software licenses.