Add 'g amend' (and also 'g ammend' because I have trouble spelling that one)

README.md

@@ -38,6 +38,7 @@ g | git equivalent
 g commit | Prompts for commit message inline, rather than opening a text editor
 g commit *message* | git commit -m *message*
 g uncommit | git reset --soft HEAD~1
+g ammend | git commit --amend --no-edit
 g branch *branch* | stashes working tree, creates or switches branch, and checks out branch
 g rmbranch *branch* | git branch -d *branch* *TODO: rename?*
 g tag *tag* | git tag *tag*

bin/g

@@ -167,6 +167,10 @@ uncommit)
     git reset --soft HEAD~1
 ;;
 
+amend | ammend)
+git commit --amend --no-edit
+;;
+
 '@' | branch)
 echo 'Switching to branch'
 if [ -z "$2" ]; then