drop support for Ruby < v2.6

Author: syoder

.travis.yml

@@ -3,22 +3,16 @@ bundler_args: --binstubs --jobs=3 --retry=3
 cache: bundler
 sudo: false
 before_install:
-  - gem i rubygems-update -v '<3' && update_rubygems
-  # from travis docs, to use bundler 1.x:
-  - gem uninstall -v '>= 2' -i $(rvm gemdir)@global -ax bundler || true
-  - gem install bundler -v '< 2'
+  - gem update --system
+  - gem install bundler
 before_script:
   - "bin/ci-code-review"
 script: bin/ci
 rvm:
-  - 2.5.0
+  - 2.6
+  - 2.7
 env:
   - RAILS_VERSION='~> 5.2.0'
   - RAILS_VERSION='5-2-stable'
 matrix:
-  include:
-    - rvm: 2.2.3
-      env: RAILS_VERSION='~> 5.2.0'
-    - rvm: 2.4.4
-      env: RAILS_VERSION='~> 4.2.10'
   fast_finish: true

kracken.gemspec

@@ -19,7 +19,7 @@ Gem::Specification.new do |s|
   s.bindir      = "exe"
   s.executables = s.files.grep(%r{^exe/}) { |f| File.basename(f) }
 
-  s.add_dependency 'rails', [">= 4.0", "< 6.0"]
+  s.add_dependency 'rails', [">= 5.2", "< 6.0"]
   s.add_dependency 'omniauth', '~> 1.0'
   s.add_dependency 'faraday', '~> 0.8'
   s.add_dependency 'omniauth-oauth2', '~> 1.1'