Update README with call info.

Signed-off-by: François de Metz <francois@stormz.me>
Remove disclaimer.

Signed-off-by: François de Metz <francois@stormz.me>
Add install doc.

Signed-off-by: François de Metz <francois@stormz.me>
Rename the package to hubot-ping-standup.

Signed-off-by: François de Metz <francois@stormz.me>