Add how to install rack-test from github to README.

To explain users about the way to install unreleased version.
rack · Jun 18, 2017 · 9c643e7 · 9c643e7
1 parent 1c78259
commit 9c643e7
Showing 1 changed file with 13 additions and 2 deletions.
diff --git a/README.md b/README.md
@@ -72,11 +72,22 @@ end
 
 To install the latest release as a gem:
 
-`gem install rack-test`
+```
+gem install rack-test
+```
 
 Or via Bundler:
 
-`gem "rack-test", require: "rack/test"`
+```
+gem 'rack-test', require: 'rack/test'
+```
+
+Or to install unreleased version via Bundler:
+
+```
+gem 'rack-test', github: 'rack-test', branch: 'master'
+gem 'rack-test', github: 'rack-test', ref: 'a5aa1e5'
+```
 
 ## Authors