Updated readme with instructions

Readme.md

 This is a repositiory to hold code about and discuss our independent
 study on kernels.
+
+Run cross.sh to set up gcc cross-compiler
+
+The following are commands for compiling and running the assembly:
+
+nasm boot.asm -f bin -o boot.bin
+qemu-system-i386 boot.bin
\ No newline at end of file