make inclusion of sinatra optional

CHANGELOG.md

@@ -1,6 +1,13 @@
 # Change Log
 All notable changes to this project will be documented in this file.
 
+
+## [6.0.0] - date TBD ##
+### BREAKING CHANGE
+- The sinatra gem is no longer specified as a dependency of this gem.
+  If you would like to use the inbound processing, you must add this gem
+  to your Gemfile. e.g. `gem 'sinatra', '>= 1.4.7', '< 3'`
+
 ## [5.2.0] - 2017-10-30 ##
 ### Added
 - PR #234: Helpers for email statistics - global, category, subuser 

README.md

@@ -68,7 +68,6 @@ gem install sendgrid-ruby
 ## Dependencies
 
 - [Ruby-HTTP-Client](https://github.com/sendgrid/ruby-http-client)
-- [Sinatra](http://www.sinatrarb.com/) - this is only needed if you plan to process [Inbound Email](#inbound).
 
 <a name="quick-start"></a>
 # Quick Start

lib/sendgrid/helpers/inbound/README.md

@@ -8,6 +8,19 @@
 * [Contributing](#contributing)
 
 <a name="quick_start_local_sample"></a>
+
+
+# Installation
+
+In addition to the installation instructions in
+[the main readme](https://github.com/sendgrid/sendgrid-ruby/tree/master/#installation),
+you must also add sinatra to your Gemfile:
+
+```
+gem 'sinatra', '>= 1.4.7', '< 3'
+```
+
+
 # Quick Start for Local Testing with Sample Data
 
 ```bash

lib/sendgrid/helpers/inbound/app.rb

@@ -1,4 +1,16 @@
-require 'sinatra'
+begin
+  require 'sinatra'
+rescue LoadError
+  puts <<-NOTE
+    As of sengrid verison 6, sinatra is no longer specified as a dependency of
+    the sendgrid gem. All the functionality of the inbound server is still the same
+    and fully supported, but you just need to include the sinatra dependency in your gemfile
+    yourself, like so:
+
+        gem 'sinatra', '>= 1.4.7', '< 3'
+  NOTE
+  raise
+end
 require 'logger'
 require 'json'
 require 'yaml'

sendgrid-ruby.gemspec

@@ -20,7 +20,7 @@ Gem::Specification.new do |spec|
   spec.test_files    = spec.files.grep(/^(test|spec|features)/)
   spec.require_paths = ['lib']
   spec.add_dependency 'ruby_http_client', '~> 3.3.0'
-  spec.add_dependency 'sinatra', '>= 1.4.7', '< 3'
+  spec.add_development_dependency 'sinatra', '>= 1.4.7', '< 3'
   spec.add_development_dependency 'rake', '~> 0'
   spec.add_development_dependency 'rspec'
   spec.add_development_dependency 'pry'