#7 fix hash for github requests

lib/getPackageDetails.js

@@ -84,7 +84,7 @@ function getSizeAndLicenseFromGitHub(owner, repo) {
  * @returns {object} dependencies, name, version
  */
 function getPackageJsonFromGitHub(owner, repo, ref) {
-  const packageJsonUrl = `${gitHubApiUrl}repos/${owner}/${repo}/contents/package.json?ref=${ref}`;// I believe size of downloaded repo will not depend on ref
+  const packageJsonUrl = `${gitHubApiUrl}repos/${owner}/${repo}/contents/package.json?ref=${ref}`;
   readline.cursorTo(process.stdout, 0);
   readline.clearLine(process.stdout, 1);
   process.stdout.write(`GET ${packageJsonUrl}`);
@@ -120,8 +120,10 @@ function getPackageDetailsFromGitHub({ host, path, hash, protocol }, versionLoos
   if (!owner || !repo) {
     throw new Error(`Cannot parse github dependency url ${versionLoose}`)
   }
-  const ref = hash || 'master';
-  // const key = ['github', owner, repo, ref];
+  let ref = 'master';
+  if (hash && hash.slice(1)) {
+    ref = hash.slice(1);
+  }
   return Promise.all([
     getSizeAndLicenseFromGitHub(owner, repo),
     getPackageJsonFromGitHub(owner, repo, ref)