Add upstream remotes setup

.gitremotes

@@ -0,0 +1,5 @@
+# [remote "upstream"]
+#     url = https://github.com/username/repository
+#     fetch = +refs/heads/*:refs/remotes/repository/*
+# [alias]
+#     merge-upstream = pull --no-edit upstream branch

README.md

@@ -1,2 +1,7 @@
 # Xtreme-Apps
 Bundle of external apps tweaked for Xtreme
+
+### Setup branch upstream remotes:
+```sh
+git config --local include.path ../.gitremotes
+```