add special method that lists available actions for client

lib/gitlab.rb

@@ -26,4 +26,12 @@ def self.method_missing(method, *args, &block)
   def self.respond_to?(method)
     return client.respond_to?(method) || super
   end
+
+  # Returns an unsorted array of available client methods.
+  #
+  # @return [Array<Symbol>]
+  def self.actions
+    hidden = /endpoint|private_token|user_agent|sudo|get|post|put|\Adelete\z|validate|set_request_defaults/
+    (Gitlab::Client.instance_methods - Object.methods).reject {|e| e[hidden]}
+  end
 end

spec/gitlab_spec.rb

@@ -9,6 +9,15 @@
     end
   end
 
+  describe ".actions" do
+    it "should return an array of client methods" do
+      actions = Gitlab.actions
+      expect(actions).to be_an Array
+      expect(actions.first).to be_a Symbol
+      expect(actions.sort.first).to match(/add_/)
+    end
+  end
+
   describe ".endpoint=" do
     it "should set endpoint" do
       Gitlab.endpoint = 'https://api.example.com'