Implement git refs API for listing references (branches, tags and other) (#5354)

* Inital routes to git refs api

* Git refs API implementation

* Update swagger

* Fix copyright

* Make swagger happy add basic test

* Fix test

* Fix test again :)

vendor/gopkg.in/src-d/go-git.v4/plumbing/memory.go

@@ -0,0 +1,61 @@
+package plumbing
+
+import (
+	"bytes"
+	"io"
+	"io/ioutil"
+)
+
+// MemoryObject on memory Object implementation
+type MemoryObject struct {
+	t    ObjectType
+	h    Hash
+	cont []byte
+	sz   int64
+}
+
+// Hash returns the object Hash, the hash is calculated on-the-fly the first
+// time it's called, in all subsequent calls the same Hash is returned even
+// if the type or the content have changed. The Hash is only generated if the
+// size of the content is exactly the object size.
+func (o *MemoryObject) Hash() Hash {
+	if o.h == ZeroHash && int64(len(o.cont)) == o.sz {
+		o.h = ComputeHash(o.t, o.cont)
+	}
+
+	return o.h
+}
+
+// Type return the ObjectType
+func (o *MemoryObject) Type() ObjectType { return o.t }
+
+// SetType sets the ObjectType
+func (o *MemoryObject) SetType(t ObjectType) { o.t = t }
+
+// Size return the size of the object
+func (o *MemoryObject) Size() int64 { return o.sz }
+
+// SetSize set the object size, a content of the given size should be written
+// afterwards
+func (o *MemoryObject) SetSize(s int64) { o.sz = s }
+
+// Reader returns a ObjectReader used to read the object's content.
+func (o *MemoryObject) Reader() (io.ReadCloser, error) {
+	return ioutil.NopCloser(bytes.NewBuffer(o.cont)), nil
+}
+
+// Writer returns a ObjectWriter used to write the object's content.
+func (o *MemoryObject) Writer() (io.WriteCloser, error) {
+	return o, nil
+}
+
+func (o *MemoryObject) Write(p []byte) (n int, err error) {
+	o.cont = append(o.cont, p...)
+	o.sz = int64(len(o.cont))
+
+	return len(p), nil
+}
+
+// Close releases any resources consumed by the object when it is acting as a
+// ObjectWriter.
+func (o *MemoryObject) Close() error { return nil }