Modify the Gemfile for testing with mime-types 3

-   Also modify the appraisals to be more flexibly specified.
-   The specs are '>= 1.16' and '< 4.0' because the major versions of
    mime-types have steadily restricted the supported versions of Ruby at a
    different rate than Rails. The Appraisal for Rails 5 can be specified as
    either '>= 2.0, '< 4.0' or '~> 3.0' depending on how other gems restrict
    mime-types versions.

    -   mime-types 1.x supports any version of Ruby, but no longer receives any
        updates (it hit EOL on 27 October 2015).
    -   mime-types 2.x supports Ruby >= 1.9.2, but will only receive security
        and data updates until 21 November 2017.
    -   mime-types 3.x supports Ruby >= 2.0 and is the active development
        version of mime-types.

-   The APIs that paperclip uses are compatible between all three versions of
    mime-types.

Appraisals

@@ -1,9 +1,17 @@
 appraise "4.2.awsv2.1" do
   gem "rails", "~> 4.2.0"
   gem "aws-sdk", "~> 2.1.0"
+
+  group :development, :test do
+    gem 'mime-types', '>= 1.16', '< 4'
+  end
 end
 
 appraise "4.2.awsv2.0" do
   gem "rails", "~> 4.2.0"
   gem "aws-sdk", "~> 2.0.0"
+
+  group :development, :test do
+    gem 'mime-types', '>= 1.16', '< 4'
+  end
 end

Gemfile

@@ -9,7 +9,7 @@ gem 'pry'
 # Prevents bundler from taking a long-time to resolve
 group :development, :test do
   gem 'activerecord-import'
-  gem 'mime-types', '~> 1.16'
+  gem 'mime-types'
   gem 'builder'
   gem 'rubocop', require: false
 end

gemfiles/4.2.awsv2.0.gemfile

@@ -9,7 +9,7 @@ gem "aws-sdk", "~> 2.0.0"
 
 group :development, :test do
   gem "activerecord-import"
-  gem "mime-types", "~> 1.16"
+  gem "mime-types", ">= 1.16", "< 4"
   gem "builder"
   gem "rubocop", :require => false
 end

gemfiles/4.2.awsv2.1.gemfile

@@ -9,7 +9,7 @@ gem "aws-sdk", "~> 2.1.0"
 
 group :development, :test do
   gem "activerecord-import"
-  gem "mime-types", "~> 1.16"
+  gem "mime-types", ">= 1.16", "< 4"
   gem "builder"
   gem "rubocop", :require => false
 end