##Warmup
One Missing: Write a function that takes an array of integers between 1 and 10, with one missing integer, as an argument and returns the missing integer. Test this with Mocha and Chai.
##Warmup
One Missing: Write a function that takes an array of integers between 1 and 10, with one missing integer, as an argument and returns the missing integer. Test this with Mocha and Chai.