Cannot run Sinatra application on port 80

I am trying to run some blog software I wrote on port 80 like this: ruby tinyblog.rb -o 80

Only problem is that I get this error: [2014-05-24 01:04:34] INFO WEBrick 1.3.1 [2014-05-24 01:04:34] INFO ruby 2.1.2 (2014-05-08) [x86_64-linux] /home/user/.rvm/rubies/ruby-2.1.2/lib/ruby/2.1.0/socket.rb:206:in bind': Permission denied - bind(2) for 127.0.0.1:80 (Errno::EACCES) from /home/user/.rvm/rubies/ruby-2.1.2/lib/ruby/2.1.0/socket.rb:206:in listen’ from /home/user/.rvm/rubies/ruby-2.1.2/lib/ruby/2.1.0/socket.rb:461:in block in tcp_server_sockets' from /home/user/.rvm/rubies/ruby-2.1.2/lib/ruby/2.1.0/socket.rb:232:in each’ from /home/user/.rvm/rubies/ruby-2.1.2/lib/ruby/2.1.0/socket.rb:232:in foreach' from /home/user/.rvm/rubies/ruby-2.1.2/lib/ruby/2.1.0/socket.rb:459:in tcp_server_sockets’ from /home/user/.rvm/rubies/ruby-2.1.2/lib/ruby/2.1.0/webrick/utils.rb:75:in create_listeners' from /home/user/.rvm/rubies/ruby-2.1.2/lib/ruby/2.1.0/webrick/server.rb:132:in listen’ from /home/user/.rvm/rubies/ruby-2.1.2/lib/ruby/2.1.0/webrick/server.rb:113:in initialize' from /home/user/.rvm/rubies/ruby-2.1.2/lib/ruby/2.1.0/webrick/httpserver.rb:45:in initialize’ from /home/user/.rvm/gems/ruby-2.1.2/gems/rack-1.5.2/lib/rack/handler/webrick.rb:11:in new' from /home/user/.rvm/gems/ruby-2.1.2/gems/rack-1.5.2/lib/rack/handler/webrick.rb:11:in run’ from /home/user/.rvm/gems/ruby-2.1.2/gems/sinatra-1.4.5/lib/sinatra/base.rb:1497:in start_server' from /home/user/.rvm/gems/ruby-2.1.2/gems/sinatra-1.4.5/lib/sinatra/base.rb:1435:in run!’ from /home/user/.rvm/gems/ruby-2.1.2/gems/sinatra-1.4.5/lib/sinatra/main.rb:25:in `block in module:Sinatra’

How do I fix this? The application can be found at http://github.com/Quojil/TinyBlog if need be.