Required tarantool version

[VifleY]

Create command uses tarantool built-in fio.mktree(), which is not accesible via tarantool version < 1.9 (tested with 1.6, 1.7.6, 1.7-centos and 1.8.1)

Actually fio.mktree() is specified in docs on 1.7 (http://www.tarantool.io:8090/ru/doc/1.7/reference/reference_lua/fio/#fio-mktree)
But I am still unable to call it (using official docker image 1.7.6):

/opt/tarantool # tarantool
Tarantool 1.7.6-0-g7b2945d6c
type 'help' for interactive help
tarantool> require('fio').mktree
---
- null
...

Error stacktrace:

/usr/local/share/lua/5.1/tarantoolapp/commands/create.lua:232: attempt to call field 'mktree' (a nil value)
stack traceback:
	...lib/luarocks/rocks/tarantoolapp/1.0.2-1/bin/tarantoolapp:54: in function 'mktree'
	/usr/local/share/lua/5.1/tarantoolapp/commands/create.lua:232: in function 'run'
	...lib/luarocks/rocks/tarantoolapp/1.0.2-1/bin/tarantoolapp:51: in function <...lib/luarocks/rocks/tarantoolapp/1.0.2-1/bin/tarantoolapp:48>
	[C]: in function 'xpcall'
	...lib/luarocks/rocks/tarantoolapp/1.0.2-1/bin/tarantoolapp:47: in main chunk

Suggestion: specify required tarantool version