[GSoC 2019] kubectl plugin for the Postgres operator (#579)

*  Add a prototype of a kubectl plugin for the Postgres operator
   Work done by Vineeth Pothulapati <vineethpothulapati@outlook.com>
   during Google Summer of Code 2019

kubectl-pg/cmd/root.go

@@ -0,0 +1,50 @@
+/*
+Copyright © 2019 Vineeth Pothulapati <vineethpothulapati@outlook.com>
+
+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.
+*/
+
+package cmd
+
+import (
+	"fmt"
+	"github.com/spf13/cobra"
+	"github.com/spf13/viper"
+	"os"
+)
+
+var rootCmd = &cobra.Command{
+	Use:   "kubectl-pg",
+	Short: "kubectl plugin for the Zalando Postgres operator.",
+	Long:  `kubectl pg plugin for interaction with Zalando postgres operator.`,
+}
+
+// Execute adds all child commands to the root command and sets flags appropriately.
+// This is called by main.main(). It only needs to happen once to the rootCmd.
+func Execute() {
+	if err := rootCmd.Execute(); err != nil {
+		fmt.Println(err)
+		os.Exit(1)
+	}
+}
+
+func init() {
+	viper.SetDefault("author", "Vineeth Pothulapati <vineethpothulapati@outlook.com>")
+	viper.SetDefault("license", "mit")
+}