Added Tagging and Versioning exercise

Author: Gabriel Schenker

tagging-and-versioning/versioning/Dockerfile

@@ -0,0 +1,7 @@
+FROM ruby:2.4.1-alpine
+RUN mkdir /app
+WORKDIR /app
+RUN gem install sinatra sinatra-contrib
+COPY . .
+EXPOSE 3000
+CMD ruby server.rb

tagging-and-versioning/versioning/server.rb

@@ -0,0 +1,32 @@
+require 'sinatra'
+require 'sinatra/namespace'  
+require 'json'
+
+set :bind, '0.0.0.0'
+set :port, 3000
+
+class Book  
+    def initialize(title, author, isbn)  
+        @title = title  
+        @author = author  
+        @isbn = isbn
+    end 
+    attr_accessor :title 
+    attr_accessor :author 
+    attr_accessor :isbn 
+    def to_json
+        {'title' => @title, 'author' => @author, 'isbn' => @isbn}.to_json
+    end
+end
+
+get '/' do  
+    'Welcome to BookList!'
+end
+
+namespace '/api/v1' do
+    get '/books' do
+        isbn = params[:isbn]
+        book = Book.new('Foundation', 'Isaac Asimov', isbn)
+        book.to_json
+    end
+end