https://www.youtube.com/watch?v=Z3A8TqGWjso&list=PLuHgQVnccGMA8iwZwrGyNXCGy2LAAsTXk
================================================================================
c22b5...=SHA-1("hi")
aaf4c...=SHA-1("hello")
aa becomes dir name under /objects
f4c... becomes object file name
"hello" is written in f4c... object file
================================================================================
vim f1.txt
write a
git add f1.txt
Git reads "a"
Git perform following
compress_out=compress("a","other_information")
hash_val=SHA_1(compress_out)
And then, write file name next to "object file name" in index
================================================================================