Hi, here's your problem today. This problem was recently asked by Facebook:

Given an array nums, write a function to move all 0's to the end of it while maintaining the relative order of the non-zero elements.

Example:

```
Input: [0,1,0,3,12]
Output: [1,3,12,0,0]
```

You must do this in-place without making a copy of the array. Minimize the total number of operations.

Here is a starting point:

```
class Solution:
def moveZeros(self, nums):
# Fill this in.
nums = [0, 0, 0, 2, 0, 1, 3, 4, 0, 0]
Solution().moveZeros(nums)
print(nums)
# [2, 1, 3, 4, 0, 0, 0, 0, 0, 0]
```