Ruby sample codes

[onoken0821]

The new documentation seems to be missing some information.

Expected Behavior

A sample code for Ruby is prepared and presented.

Current Behavior

No sample code for Ruby

Context (Environment)

bitbank-api.docs in Github

Our codes could not be connected to Bitbank websocket server with the below error message, so far.
Other company wss, such as BitFlyer, have been connedted and worked successfully.

**
/home/ec2-user/.gem/ruby/2.3.4/gems/websocket-client-simple-0.3.0/lib/websocket-client-simple/client.rb:30:in connect': SS_connect returned=1 errno=0 state=SSLv3 read server hello A: sslv3 alert handshake failure (OpenSSL::SSL::SSLError) from /home/ec2-user/.gem/ruby/2.3.4/gems/websocket-client-simple-0.3.0/lib/websocket-client-simple/client.rb:30:in connect' from /home/ec2-user/.gem/ruby/2.3.4/gems/websocket-client-simple-0.3.0/lib/websocket-client-simple/client.rb:8:in onnect'
**