Add ability to customize AppVersionCheck

Add ability to customize AppVersionCheck by @rmm5t

Add Support for Rails 6.1

Add rails 6.1 support to build matrix By @rmm5t
Correct the rails versions in the travis build matrix By @rmm5t

Fix bug with the neo4j check using the wrong Faraday Error

Fixing neo4j check Faraday Error by @ekampp #164

Adding 2.7 to the Travis test suite by @ekampp #165

Add support for Rack >=2.1

• Update status code handling for compatibility with Rack 2.1 #161

Add support for Rails 6

• @olleolleolle: gemspec: Connect to rubygems.org using HTTPS #157
• @henare: Rails 6 #160

Support for Solr 7+ health checks

#151

Add Check Collections

Merge pull request #124 from sportngin/check-collections

Adds ability to create Check Collections.

Fix deprecation warning for usage of Kernal#timeout

Merge pull request #107 from sportngin/fix-timeout-deprication

Fix deprication warning with useage of Kernal#timeout