объедините две или более историй развития вместе (Join two or more development histories together)
PRE-MERGE CHECKS
Before applying outside changes, you should get your own work in
good shape and committed locally, so it will not be clobbered if
there are conflicts. See also git-stash(1). git pull and git
merge will stop without doing anything when local uncommitted
changes overlap with files that git pull/git merge may need to
update.
To avoid recording unrelated changes in the merge commit, git
pull and git merge will also abort if there are any changes
registered in the index relative to the HEAD commit. (Special
narrow exceptions to this rule may exist depending on which merge
strategy is in use, but generally, the index must match HEAD.)
If all named commits are already ancestors of HEAD, git merge
will exit early with the message "Already up to date."
