momo5502 creat015 I updated the composer.json as above and updated using "composer update". Then in the admin panel, i enabled the English extension and it worked. So I basically followed the tutorial above and it worked fine. I doubt I can help you, if it didn't work for you.
momo5502 creat015 Actually, i know the solution. I also installed the french language pack https://github.com/maelsoucaze/flarum It seems like it installed the missing extensions.
Toby creat015 If your extensions directory is empty, delete everything and start over with a fresh installation.
momo5502 Toby A fresh installation didn't install the extensions for me. Only the french language pack did.
jordanjay29 Toby My experience is like that of @Ignivis, two composer update commands worked to populate the extensions directory.
young @Toby This condition momo5502 also happen to me.I think flarum is not update on packagist.You can see on https://packagist.org/packages/flarum/flarum .The last update time is also 2015-11-02 23:49 UTC,and the requires of flarum/composer-installer is also 0.1.0 not *.Maybe you should login in packagist to force update flarum/flarum package.
Ignivis For those, who has empty extensions directory: I had installed forum three times , but the extension directory was empty every time, after I did twice "composer update", all the extensions had appeared in the directory!
luceos young a new release of flarum/flarum is needed to update the dependency of flarum/composer-installer.
Toby young luceos Thanks guys – my bad! I've tagged a new release of flarum/flarum and it's updated on packagist now.
GOD I've said and I'll say it again... phpBB which has been around for decades... Uses composer. I really wish you would follow their path.