Update --help and readme with --list flag command

README.md

@@ -89,6 +89,15 @@ $ git solo
 Jane Doe <[email protected]>
 ```
 
+Check which co-authors you have available in your `.git-coauthors` file.
+
+```
+$ git mob --list
+jd Jane Doe [email protected]
+ad Amy Doe [email protected]
+bd Bob Doe [email protected]
+```
+
 <sup>\* [If you have git-duet installed, you'll need to uninstall it](https://github.com/findmypast-oss/git-mob/issues/2) since it conflicts with the git-solo command.</sup>
 
 Find out more with `git mob --help`

bin/mob.js

@@ -18,6 +18,7 @@ const argv = minimist(process.argv.slice(2), {
   alias: {
     h: 'help',
     v: 'version',
+    l: 'list'
   },
 });
 

src/helpers.js

@@ -14,10 +14,12 @@ function runHelp() {
     Options
       -h  Prints usage information
       -v  Prints current version
+      -l  Prints list of available co-authors
 
     Examples
       $ git mob jd     # Set John Doe as co-author
       $ git mob jd am  # Set John & Amy as co-authors
+      $ git mob -l     # Show a list of all co-authors
       $ git solo       # Dissipate the mob
   `;
   console.log(message);