[trail of bits audit] #1 Loss of precision may allow an attacker to get funds for free

contracts/lib/DecimalMath.sol

@@ -10,6 +10,7 @@ pragma experimental ABIEncoderV2;
 
 import {SafeMath} from "./SafeMath.sol";
 
+
 /**
  * @title DecimalMath
  * @author DODO Breeder
@@ -25,6 +26,10 @@ library DecimalMath {
         return target.mul(d) / ONE;
     }
 
+    function mulCeil(uint256 target, uint256 d) internal pure returns (uint256) {
+        return target.mul(d).divCeil(ONE);
+    }
+
     function divFloor(uint256 target, uint256 d) internal pure returns (uint256) {
         return target.mul(ONE).div(d);
     }