func: function approve(address _spender, uint256 _amount) public returns(bool success) {
          require((_amount == 0) || (allowance[msg.sender][_spender] == 0));
          
          if(now < (dayStart + 365 days)){
              require(msg.sender != foundersAddress && tx.origin != foundersAddress);
          }
          
          if(now < (dayStart + 180 days)){
              require(msg.sender != bonusAddress && tx.origin != bonusAddress);
          }
          
          
          allowance[msg.sender][_spender] = _amount;
          return true;
      }