Introduced in GitLab 8.15
Slack commands give users an extra interface to perform common operations
from the chat environment. This allows one to, for example, create an issue as
soon as the idea was discussed in chat.
For all available commands try the help subcommand, for example:
all review the full list of commands.
A team in Slack should be created beforehand, GitLab cannot create it for you.
Go to your project's Integrations page and select the Slack slash commands service to configure it.
Once you've followed the instructions, mark the service as active and insert the token you've received from Slack. After saving the service you are good to go!