make master and develop branch names configurable
diff --git a/git-flow b/git-flow
index 7a5c4cc..0adac5c 100755
--- a/git-flow
+++ b/git-flow
@@ -18,6 +18,10 @@
 	set -x
 fi
 
+export GITFLOW_DIR=$(dirname "$0")
+export MASTER_BRANCH=$(git config --get gitflow.branch.master || echo master)
+export DEVELOP_BRANCH=$(git config --get gitflow.branch.develop || echo develop)
+
 warn() { echo "$@" >&2; }
 die() { warn "$@"; exit 1; }
 has() { [[ " ${*:2} " == *" $1 "* ]]; }
@@ -36,8 +40,6 @@
 		exit 1
 	fi
 
-	export GITFLOW_DIR=$(dirname "$0")
-
 	# sanity checks
 	ACTION="$1"
 	BTYPE="$2"