Migrating from govendor to go dep

Change-Id: I08f2863450e141f1fed0bdef4b9ba64157c7289d
diff --git a/Gopkg.toml b/Gopkg.toml
new file mode 100644
index 0000000..b29cf9a
--- /dev/null
+++ b/Gopkg.toml
@@ -0,0 +1,58 @@
+# Copyright 2018-present Open Networking Foundation
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+# http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+
+
+# Gopkg.toml example
+#
+# Refer to https://golang.github.io/dep/docs/Gopkg.toml.html
+# for detailed Gopkg.toml documentation.
+#
+# required = ["github.com/user/thing/cmd/thing"]
+# ignored = ["github.com/user/project/pkgX", "bitbucket.org/user/project/pkgA/pkgY"]
+#
+# [[constraint]]
+#   name = "github.com/user/project"
+#   version = "1.0.0"
+#
+# [[constraint]]
+#   name = "github.com/user/project2"
+#   branch = "dev"
+#   source = "github.com/myfork/project2"
+#
+# [[override]]
+#   name = "github.com/x/y"
+#   version = "2.4.0"
+#
+# [prune]
+#   non-go = false
+#   go-tests = true
+#   unused-packages = true
+
+
+[[constraint]]
+  name = "github.com/Sirupsen/logrus"
+  version = "1.2.0"
+
+[[constraint]]
+  name = "github.com/gorilla/mux"
+  version = "1.6.2"
+
+[[constraint]]
+  name = "github.com/kelseyhightower/envconfig"
+  version = "1.3.0"
+
+[prune]
+  go-tests = true
+  unused-packages = true