Add .gitconfig & .gitignore

Signed-off-by: Josemi Liébana <josemi.liebana@westwing.de>
Add .tmux.conf

Signed-off-by: Josemi Liébana <josemi.liebana@westwing.de>
Add .vimrc.local

Signed-off-by: Josemi Liébana <josemi.liebana@westwing.de>
Add .slate

Signed-off-by: Josemi Liébana <josemi.liebana@westwing.de>