Fix problem with mime-types gem version

The latest version is not compatible with Ruby 1.9.3

Author: jonleighton

.travis.yml

@@ -2,7 +2,7 @@ language: ruby
 cache: bundler
 sudo: false
 rvm:
-  - 1.9.3
+  - 1.9.3 # when removed, get rid of the before_script hack and also the one in application_generator.rb
   - 2.0.0
   - 2.1.5
   - 2.2.0
@@ -12,4 +12,5 @@ env:
   - RAILS_VERSION="~> 4.1.0"
   - RAILS_VERSION="~> 4.2.0"
 before_script:
+  - "[ $TRAVIS_RUBY_VERSION = \"1.9.3\" ] && travis_retry gem install mime-types --version \"~> 2\" || true"
   - travis_retry gem install rails --version "$RAILS_VERSION"

lib/spring/test/application_generator.rb

@@ -58,6 +58,10 @@ def generate_files
           append_to_file(application.gemfile, "gem 'spring-commands-testunit'")
         end
 
+        if RUBY_VERSION == "1.9.3"
+          append_to_file(application.gemfile, "gem 'mime-types', '~> 2'")
+        end
+
         rewrite_file(application.gemfile) do |c|
           c.sub!("https://rubygems.org", "http://rubygems.org")
           c.gsub!(/(gem '(byebug|web-console|sdoc|jbuilder)')/, "# \\1")