Start work on interpreter

src/main.c

@@ -1,4 +1,5 @@
 #include "parser.h"
+#include "interpreter.h"
 #include <stdio.h>
 
 char* getFileContents(const char* filename) {
@@ -44,4 +45,5 @@ int main(int argc, char** argv) {
     }
     char* file = getFileContents(argv[1]);
     GroundProgram program = parseFile(file);
+    interpretGroundProgram(&program);
 }