Add link to documentation to the README.md
Add link to documentation to the README.md

Signed-off-by: Botond Dénes <a584fa4d75a0a85d721f44fb6e06315a2853b0b6@scylladb.com>
Message-Id: <7ce005042671eac1ea37da4addf042bfc584d9e2.1502268038.git.a584fa4d75a0a85d721f44fb6e06315a2853b0b6@scylladb.com>

avikivity/seastar,scylladb/seastar,cloudius-systems/seastar,syuu1228/seastar,scylladb/seastar,cloudius-systems/seastar,dreamsxin/seastar,cloudius-systems/seastar,dreamsxin/seastar,scylladb/seastar,avikivity/seastar,dreamsxin/seastar,syuu1228/seastar,avikivity/seastar,syuu1228/seastar