rename filename using regex

gistfile1.txt

rename file:
2015-01-21-hello.md
2015-04-02-word.md
to:
hello.md
word.md

for f in 2015* ; do mv $f $(echo $f | sed 's/[0-9]\{4\}-[0-9]\{2\}-[0-9]\{2\}-//') ; done