Bouncer

Bouncer.sol

pragma solidity ^0.5.8;

contract Channels {
    function deposit(address _participant) public payable;
}

contract Bouncer {
    Channels channelContract;
    address participant;
    
    constructor(Channels _channelContract, address _participant) public {
        channelContract = _channelContract;
        participant = _participant;
    }
    
    function() external payable {
        channelContract.deposit.value(msg.value)(participant);
    }
}