Base 7

Problem

Given an integer num, return a string representing its base 7 representation.

Examples

convertToBase7(49) 
// returns "100"
// In base 7, 49 translates to 7^2 + 0*7^1 + 0*7^0
// which is "100".

convertToBase7(0) 
// returns "0"
// In base 7, 0 remains 0

convertToBase7(343) 
// returns "1000"
// 343 is showcased as 7^3 + 0*7^2 + 0*7^1 + 0*7^0,