move @github to fetcher

Conflicts:
	lib/github_changelog_generator.rb

lib/github_changelog_generator/fetcher.rb

@@ -1,5 +1,40 @@
 module GitHubChangelogGenerator
   # A Fetcher responsible for all requests to GitHub and all basic manipulation with related data (such as filtering, validating, e.t.c)
+  #
+  # Example:
+  # fetcher = GitHubChangelogGenerator::Fetcher.new options
   class Fetcher
+    def initialize(options = {})
+      @options = options
+
+      @user = @options[:user]
+      @project = @options[:project]
+      @github_token = fetch_github_token
+
+      github_options = { per_page: PER_PAGE_NUMBER }
+      github_options[:oauth_token] = @github_token unless @github_token.nil?
+      github_options[:endpoint] = options[:github_endpoint] unless options[:github_endpoint].nil?
+      github_options[:site] = options[:github_endpoint] unless options[:github_site].nil?
+
+      begin
+        @github = Github.new github_options
+      rescue
+        puts GH_RATE_LIMIT_EXCEEDED_MSG.yellow
+      end
+    end
+
+    # Returns GitHub token. First try to use variable, provided by --token option, otherwise try to fetch it from CHANGELOG_GITHUB_TOKEN env variable.
+    #
+    # @return [String]
+    def fetch_github_token
+      env_var = @options[:token] ? @options[:token] : (ENV.fetch 'CHANGELOG_GITHUB_TOKEN', nil)
+
+      unless env_var
+        puts 'Warning: No token provided (-t option) and variable $CHANGELOG_GITHUB_TOKEN was not found.'.yellow
+        puts 'This script can make only 50 requests to GitHub API per hour without token!'.yellow
+      end
+
+      env_var
+    end
   end
 end