Import git repository with history

import git repo into antoher with history

git clone git@github.com:flyway/flyway.git
cd flyway
# move into another folder with rewriting the history
git filter-branch -f --prune-empty --tree-filter 'mkdir -p .root;mv * .root;mv .root root' -- --all


git clone git@github.com:regis-leray/flyway.git regis-flyway
cd regis-flyway/
git remote add origin-flyway ../flyway 
git fetch origin-flyway
git checkout -b flyway-branch origin-flyway/master
git checkout master
git merge flyway-branch