[example] Array example using a grid

[VietnameseRick]

#69

Checklist

• Create a 10x10 grid
• Allow players to move from one hex to another.
• Store the players in an Array
• Create impl to check if a player is in the Array on the location

[VietnameseRick]

I will write test for grid example in the near time

[ponderingdemocritus]

can use:

#[generate_trait]

to make code cleaner

[ponderingdemocritus]

add a brief explanation in the readme

[ponderingdemocritus]

Great start - added some comments. Could you also add some comments within the code explaining the array section.