Add alias 'gitclean'

It removes all branches that are already merged into the master branch.

Signed-off-by: Jacob Kiers <jacob@alphacomm.nl>

includes/bash_aliases.bash

@@ -15,6 +15,9 @@ alias t="tmux"
 alias x+="chmod +x"
 alias +x="chmod +x"
 
+# Remove all local branches already merged in master.
+alias gitclean='git branch --merged master | grep -v "\smaster$" | grep -v "*" | xargs git branch -d'
+
 # Detect which `ls` flavor is in use
 if ls --color > /dev/null 2>&1; then  # GNU `ls`
 	colorflag="--color"