Can't "verify and publish" the flatten token contract with the bytecode on the Kovan network.

[timothylie]

I am watching the "How to build an ICO with OpenZeppelin Part 2/2 [Revised]" Youtube video from rstormsf.

Link: https://www.youtube.com/watch?v=W8pytsIMe8A&list=PLWnAbuHy2-awkLt7stKTjuFL3cIN1SsAt&index=3&t=874s

At around the 22:00 mark on the video when I try to "verify and publish" the flatten token contract with the bytecode on the Kovan network, I get this error: 

Error! Unable to generate Contract Bytecode and ABI

Found the following ContractName(s) in source code: ERC20, ERC20Detailed, ERC20Mintable, IERC20, MinterRole, Ownable, Roles, SafeMath
But we were unable to locate a matching bytecode (err_code_2)

Here's my code on Github: https://github.com/timl206/rmn-erc20-test