Add git coauthor command

Commands.md

@@ -9,6 +9,7 @@
  - [`git chore`](#git-featurerefactorbugchore)
  - [`git clear`](#git-clear)
  - [`git clear-soft`](#git-clear-soft)
+ - [`git coauthor`](#git-coauthor)
  - [`git commits-since`](#git-commits-since)
  - [`git contrib`](#git-contrib)
  - [`git count`](#git-count)
@@ -347,6 +348,30 @@ Straight from the shell!
 git (master)> quit
 ```
 
+## git coauthor
+
+Add a co-author to the last commit
+
+```bash
+$ git coauthor user [email protected]
+
+[master b62ceae] Add documentation files
+ Date: Sat Aug 17 17:33:53 2019 -0500
+ 2 files changed, 145 insertions(+), 0 deletions(-)
+ create mode 100644 README.md
+ create mode 100644 CONTRIBUTING.md
+
+ $ git log -1
+
+commit b62ceae2685e6ece071f3c3754e9b77fd0a35c88 (HEAD -> master)
+Author: user person <[email protected]>
+Date:   Sat Aug 17 17:33:53 2019 -0500
+
+    Add documentation files
+
+    Co-authored-by: user <[email protected]>
+```
+
 ## git commits-since
 
 List commits since `date` (defaults to "last week"):

bin/git-coauthor

@@ -0,0 +1,10 @@
+#!/usr/bin/env bash
+
+coauthor=$1
+email=$2
+
+test -z $coauthor && echo "co-author required." 1>&2 && exit 1
+test -z $email && echo "co-author email required." 1>&2 && exit 1
+
+old_message="$(git log --format=%B -n1)"
+git commit --amend -m "$old_message" -m "Co-authored-by: $coauthor <$email>"

etc/git-extras-completion.zsh

@@ -196,6 +196,11 @@ _git-chore() {
         '(--remote -r)'{--remote,-r}'[setup remote tracking branch]'
 }
 
+_git-coauthor() {
+    _arguments \
+        ':co-author[co-author to add]' \
+        ':co-author-email[email address of co-author to add]'
+}
 
 _git-contrib() {
     _arguments \
@@ -441,6 +446,7 @@ zstyle ':completion:*:*:git:*' user-commands $existing_user_commands \
     chore:'create chore branch' \
     clear-soft:'soft clean up a repository' \
     clear:'rigorously clean up a repository' \
+    coauthor: 'add a co-author to the last commit' \
     commits-since:'show commit logs since some date' \
     contrib:'show user contributions' \
     count:'show commit count' \

man/git-coauthor.1

@@ -0,0 +1,42 @@
+.\" generated with Ronn/v0.7.3
+.\" http://github.com/rtomayko/ronn/tree/0.7.3
+.
+.TH "GIT\-COAUTHOR" "1" "August 2019" "" "Git Extras"
+.
+.SH "NAME"
+\fBgit\-coauthor\fR \- Add a co\-author to the last commit
+.
+.SH "SYNOPSIS"
+\fBgit\-coauthor\fR <co\-author> <co\-author\-email>
+.
+.SH "DESCRIPTION"
+Add a co\-author to the last commit
+.
+.SH "OPTIONS"
+<co\-author>
+.
+.P
+The username of the co\-author you want to add\.
+.
+.P
+<co\-author\-email>
+.
+.P
+The email address of the author you want to add\.
+.
+.SH "EXAMPLES"
+.
+.nf
+
+$ git coauthor user user@email\.com
+.
+.fi
+.
+.SH "AUTHOR"
+Written by Jacob Herrington \fIjacobherringtondeveloper@gmail\.com\fR
+.
+.SH "REPORTING BUGS"
+<\fIhttps://github\.com/tj/git\-extras/issues\fR>
+.
+.SH "SEE ALSO"
+<\fIhttps://github\.com/tj/git\-extras\fR>

man/git-coauthor.md

@@ -0,0 +1,36 @@
+git-coauthor(1) -- Add a co-author to the last commit
+================================
+
+## SYNOPSIS
+
+`git-coauthor` <co-author> <co-author-email>
+
+## DESCRIPTION
+
+  Add a co-author to the last commit
+
+## OPTIONS
+
+  <co-author>
+
+  The username of the co-author you want to add.
+
+  <co-author-email>
+
+  The email address of the author you want to add.
+
+## EXAMPLES
+
+    $ git coauthor user [email protected]
+
+## AUTHOR
+
+Written by Jacob Herrington <[email protected]>
+
+## REPORTING BUGS
+
+&lt;<https://github.com/tj/git-extras/issues>&gt;
+
+## SEE ALSO
+
+&lt;<https://github.com/tj/git-extras>&gt;

man/git-extras.md

@@ -31,6 +31,7 @@ git-extras(1) -- Awesome GIT utilities
    - **git-chore(1)** Create chore branch
    - **git-clear-soft(1)** Soft clean up a repository
    - **git-clear(1)** Rigorously clean up a repository
+   - **git-coauthor(1)** Add a co-author to the last commit
    - **git-commits-since(1)** Show commit logs since some date
    - **git-contrib(1)** Show user's contributions
    - **git-count(1)** Show commit count

man/index.txt

@@ -9,6 +9,7 @@ git-changelog(1) git-changelog
 git-chore(1) git-chore
 git-clear-soft(1) git-clear-soft
 git-clear(1) git-clear
+git-coauthor(1) git-coauthor
 git-commits-since(1) git-commits-since
 git-contrib(1) git-contrib
 git-count(1) git-count