Merge branch 'update-readme' into 'master'

Update readme

See merge request totem/website!62

README.md

 Simple website to show TOTEM to the world.
 
+
 ## Setting up
 
+### Requirements
+
+ * ruby
+
+   Can be installed using you distributions packet manager or
+   [ruby version manager](https://rvm.io).
+   In case your locally installed verions of ruby doesn't work,
+   try to use rvm with ruby 2.4.2
+   ```
+   rvm install ruby-2.4.2
+   rvm use 2.4.2
+   ```
+ * rubygem-bundler
+
+   install bundler using your local packet manager or
+   ```
+   gem install bundler
+   ```
+
+### Start
+
 To see the website, clone this repository and type the following commands:
 
 ```
-$ bundle install --path vendor/bundle     # Install dependencies
 $ rake getcourses                         # Get course data from edX
 $ bundle exec middleman serve             # Start development web server
 ```