Add checks to make sure canasta's requirements are met

* Check that we're running as root (though, I'm not sure it is necessary when you are running a
  non-root container system)
* Check that we have docker-compose installed before attempting create
* Oh, and btw, update gitignore for emacs files

.gitignore

@@ -13,3 +13,8 @@
 
 # Dependency directories (remove the comment below to include it)
 # vendor/
+
+# Emacs
+*~
+.#*
+\#*#

cmd/create/create.go

@@ -3,6 +3,7 @@ package create
 import (
 	"fmt"
 	"os"
+	"os/exec"
 
 	"github.com/spf13/cobra"
 
@@ -23,7 +24,13 @@ func NewCmdCreate() *cobra.Command {
 	createCmd := &cobra.Command{
 		Use:   "create",
 		Short: "Create a Canasta installation",
-		Long:  `Creates a Canasta installation using an orchestrator of your choice.`,
+		Long:  "Creates a Canasta installation using an orchestrator of your choice.",
+		PreRun: func(cmd *cobra.Command, args []string) {
+			_, err := exec.LookPath("docker-compose")
+			if err != nil {
+				logging.Fatal(fmt.Errorf("docker-compose should be installed! (%s)", err))
+			}
+		},
 		RunE: func(cmd *cobra.Command, args []string) error {
 			if canastaInfo, err = mediawiki.PromptUser(canastaInfo); err != nil {
 				logging.Fatal(err)

internal/logging/logging.go

@@ -6,6 +6,7 @@ import (
 	"io/ioutil"
 	"log"
 	"os"
+	"os/user"
 	"syscall"
 )
 
@@ -121,8 +122,18 @@ func init() {
 	directory = "/etc/canasta"
 	confFile = directory + "/conf.json"
 
+	// Verifies that this is running as root
+	currentUser, err := user.Current()
+	if err != nil {
+		errReport := fmt.Errorf("Unable to get the current user: %s", err)
+		Fatal(errReport)
+	}
+	if currentUser.Username != "root" {
+		Fatal(fmt.Errorf("This program must be run as root."))
+	}
+
 	// Checks for the conf.json file
-	_, err := os.Stat(confFile)
+	_, err = os.Stat(confFile)
 	if os.IsNotExist(err) {
 		// Check for the configuration folder
 		_, err = os.Stat(directory)