Fix loadpath for grape

see ruby-grape/grape#1758

grape/grape.gemspec

@@ -0,0 +1,25 @@
+$LOAD_PATH.unshift File.expand_path('../lib', __FILE__)
+require 'grape/version'
+
+Gem::Specification.new do |s|
+  s.name        = 'grape'
+  s.version     = Grape::VERSION
+  s.platform    = Gem::Platform::RUBY
+  s.authors     = ['Michael Bleigh']
+  s.email       = ['[email protected]']
+  s.homepage    = 'https://github.com/ruby-grape/grape'
+  s.summary     = 'A simple Ruby framework for building REST-like APIs.'
+  s.description = 'A Ruby framework for rapid API development with great conventions.'
+  s.license     = 'MIT'
+
+  s.add_runtime_dependency 'rack', '>= 1.3.0'
+  s.add_runtime_dependency 'mustermann-grape', '~> 1.0.0'
+  s.add_runtime_dependency 'rack-accept'
+  s.add_runtime_dependency 'activesupport'
+  s.add_runtime_dependency 'virtus', '>= 1.0.0'
+  s.add_runtime_dependency 'builder'
+
+  s.files         = Dir['**/*'].keep_if { |file| File.file?(file) }
+  s.test_files    = Dir['spec/**/*']
+  s.require_paths = ['lib']
+end