envsetup: Add githubremote function

* Useful for picking changes from our repositories
  to AOSP based repositories before forking them

Change-Id: I4f1d733354591fd3db431dd590ccf46e12f6a342

build/envsetup.sh

@@ -10,6 +10,7 @@ Additional LineageOS functions:
 - lineageremote:   Add git remote for LineageOS Gerrit Review.
 - aospremote:      Add git remote for matching AOSP repository.
 - cafremote:       Add git remote for matching CodeAurora repository.
+- githubremote:    Add git remote for LineageOS Github.
 - mka:             Builds using SCHED_BATCH on all processors.
 - mkap:            Builds the module(s) using mka and pushes them to the device.
 - cmka:            Cleans and builds using mka.
@@ -343,6 +344,27 @@ function cafremote()
     echo "Remote 'caf' created"
 }
 
+function githubremote()
+{
+    if ! git rev-parse --git-dir &> /dev/null
+    then
+        echo ".git directory not found. Please run this from the root directory of the Android repository you wish to set up."
+        return 1
+    fi
+    git remote rm github 2> /dev/null
+    local REMOTE=$(git config --get remote.aosp.projectname)
+
+    if [ -z "$REMOTE" ]
+    then
+        REMOTE=$(git config --get remote.caf.projectname)
+    fi
+
+    local PROJECT=$(echo $REMOTE | sed -e "s#platform/#android/#g; s#/#_#g")
+
+    git remote add github https://github.com/LineageOS/$PROJECT
+    echo "Remote 'github' created"
+}
+
 function installboot()
 {
     if [ ! -e "$OUT/recovery/root/etc/recovery.fstab" ];