lerentis's changes (#12)

Changes from lerentis's fork.

Co-authored-by: Tobias Trabelsi <lerentis@uploadfilter24.eu>
Reviewed-on: https://gitea.com/gitea/terraform-provider-gitea/pulls/12

examples/pre-receive.sh

@@ -0,0 +1,9 @@
+#!/bin/bash
+while read oldrev newrev refname
+do
+    branch=$(git rev-parse --symbolic --abbrev-ref $refname)
+    if [ "master" = "$branch" ]; then
+        echo "wrong branch"
+        exit 1
+    fi
+done