Add paragraph to repeatString describing arguments

Author: msespos

02_repeatString/README.md

@@ -6,6 +6,10 @@ Write a function that simply repeats the string a given number of times:
 repeatString('hey', 3) // returns 'heyheyhey'
 ```
 
+This function will take two arguments, `string` and `num`.
+
+*Note:* The exercises after this one will not have arguments provided as this one does - you will need to provide them yourself from now on. So read each exercise's README carefully to see what kinds of arguments will be expected.
+
 You will notice in this exercise that there are multiple tests (see in file `repeatString.spec.js`). Only the first test is currently enabled. So after making sure that this first one passes, enable the others one by one by deleting the `.skip` from the `test.skip()` function.