Make it possible to configure api_key

lib/telebugs.rb

@@ -1,8 +1,15 @@
 # frozen_string_literal: true
 
 require_relative "telebugs/version"
+require_relative "telebugs/config"
 
 module Telebugs
-  class Error < StandardError; end
-  # Your code goes here...
+  # The general error that this library uses when it wants to raise.
+  Error = Class.new(StandardError)
+
+  class << self
+    def configure
+      yield Telebugs::Config.instance
+    end
+  end
 end

lib/telebugs/config.rb

@@ -0,0 +1,21 @@
+# frozen_string_literal: true
+
+module Telebugs
+  # Represents the Telebugs config. A config contains all the options that you
+  # can use to configure a +Telebugs::Notifier+ instance.
+  class Config
+    attr_accessor :api_key
+
+    class << self
+      attr_writer :instance
+
+      def instance
+        @instance ||= new
+      end
+    end
+
+    def initialize
+      @api_key = nil
+    end
+  end
+end

test/test_telebugs.rb

@@ -6,4 +6,14 @@ class TestTelebugs < Minitest::Test
   def test_that_it_has_a_version_number
     refute_nil ::Telebugs::VERSION
   end
+
+  def test_configure_configures_project_key
+    key = "12345:abcdef"
+
+    Telebugs.configure do |config|
+      config.api_key = key
+    end
+
+    assert_equal key, Telebugs::Config.instance.api_key
+  end
 end