Fix gatsby dev round #2 (#762)

* Add missing dependency configstore

* Add note about needing to set path to cloned repo

* Fix gatsby-dev logic

packages/gatsby-dev-cli/bin/gatsby-dev

@@ -1,36 +1,42 @@
 #!/usr/bin/env node
 
-const Configstore = require('configstore');
-const pkg = require('../package.json');
-var argv = require('yargs').array('packages').argv;
+const Configstore = require("configstore");
+const pkg = require("../package.json");
+var argv = require("yargs").array("packages").argv;
 
 const conf = new Configstore(pkg.name);
 
-const gatsbyLocation = conf.get('gatsby-location');
+if (argv.setPathToRepo) {
+  console.log("Saving path to your Gatsby repo");
+  conf.set("gatsby-location", argv.setPathToRepo);
+  process.exit();
+}
+
+const gatsbyLocation = conf.get("gatsby-location");
 
 if (!gatsbyLocation) {
-        console.log(`
+  console.log(
+    `
 You haven't set the path yet to your cloned
 version of Gatsby. Do so now by running:
 
 gatsby-dev --set-path-to-repo /path/to/my/cloned/version/gatsby
-        `)
-        process.exit()
-}
-
-if (argv.setPathToRepo) {
-  console.log('setting path to repo')
-  conf.set('gatsby-location', argv.setPathToRepo)
+        `
+  );
+  process.exit();
 }
 
 if (!argv.packages) {
-        console.log(`
+  console.log(
+    `
 You probably want to pass in a list of packages to start
 developing on! For example:
 
 gatsby-dev --packages gatsby gatsby-typegen-remark
-`)
+`
+  );
+  process.exit();
 }
 
-const watch = require('../')
-watch(gatsbyLocation, argv.packages)
+const watch = require("../");
+watch(gatsbyLocation, argv.packages);