Problem Uploading Code to Uno

I'm making a very simple program for a class I'm running, however whenever I try to upload my code to my Uno I am met with this error message.

avrdude: no programmer has been specified on the command line or the config file
         Specify a programmer using the -c option and try again

I've checked the port and board setting are correct, and I'm just using a USB no external program, so I'm not sure what is wrong?

For reference here is my whole code

int front1 = 2;
int front2 = 3;

int back1 = 4;
int back2 = 5;

void setup() {
  pinMode(front1, OUTPUT);
  pinMode(front2, OUTPUT);
  pinMode(back1, OUTPUT);
  pinMode(back2, OUTPUT);




}

void loop() {
  digitalWrite(front1, HIGH);
  delay(1000);
}

(deleted)

Incompatibility between the version of the IDE you're using and the version of AVR boards that you updated to.

Either downgrade avr boards, or update to current IDE version (1.6.12)