Add a config backend base class.

Author: arthurschreiber

ext/rugged/rugged.c

@@ -467,6 +467,7 @@ void Init_rugged(void)
 	Init_rugged_branch();
 	Init_rugged_branch_collection();
 	Init_rugged_config();
+	Init_rugged_config_backend();
 	Init_rugged_remote();
 	Init_rugged_remote_collection();
 	Init_rugged_notes();

ext/rugged/rugged.h

@@ -65,6 +65,7 @@ void Init_rugged_revwalk(void);
 void Init_rugged_reference(void);
 void Init_rugged_reference_collection(void);
 void Init_rugged_config(void);
+void Init_rugged_config_backend(void);
 void Init_rugged_remote(void);
 void Init_rugged_remote_collection(void);
 void Init_rugged_notes(void);

ext/rugged/rugged_config_backend.c

@@ -0,0 +1,33 @@
+/*
+ * The MIT License
+ *
+ * Copyright (c) 2015 GitHub, Inc
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#include "rugged.h"
+
+extern VALUE rb_cRuggedConfig;
+VALUE rb_cRuggedConfigBackend;
+
+void Init_rugged_config_backend(void)
+{
+	rb_cRuggedConfigBackend = rb_define_class_under(rb_cRuggedConfig, "Backend", rb_cObject);
+}