remove Gemfile.lock and adjust .gitignore

.gitignore

@@ -1,5 +1,6 @@
 .DS_Store
 coverage/
+Gemfile.lock
 .buildpath
 .project
 .settings/

Gemfile.lock

@@ -1,72 +0,0 @@
-GEM
-  remote: https://rubygems.org/
-  specs:
-    actionpack (5.2.4.2)
-      actionview (= 5.2.4.2)
-      activesupport (= 5.2.4.2)
-      rack (~> 2.0, >= 2.0.8)
-      rack-test (>= 0.6.3)
-      rails-dom-testing (~> 2.0)
-      rails-html-sanitizer (~> 1.0, >= 1.0.2)
-    actionview (5.2.4.2)
-      activesupport (= 5.2.4.2)
-      builder (~> 3.1)
-      erubi (~> 1.4)
-      rails-dom-testing (~> 2.0)
-      rails-html-sanitizer (~> 1.0, >= 1.0.3)
-    activesupport (5.2.4.2)
-      concurrent-ruby (~> 1.0, >= 1.0.2)
-      i18n (>= 0.7, < 2)
-      minitest (~> 5.1)
-      tzinfo (~> 1.1)
-    builder (3.2.4)
-    concurrent-ruby (1.1.8)
-    crass (1.0.6)
-    erubi (1.10.0)
-    i18n (1.8.5)
-      concurrent-ruby (~> 1.0)
-    loofah (2.9.0)
-      crass (~> 1.0.2)
-      nokogiri (>= 1.5.9)
-    method_source (1.0.0)
-    minitest (5.14.4)
-    nokogiri (1.11.2-x86_64-darwin)
-      racc (~> 1.4)
-    racc (1.5.2)
-    rack (2.2.3)
-    rack-test (1.1.0)
-      rack (>= 1.0, < 3)
-    rails-dom-testing (2.0.3)
-      activesupport (>= 4.2.0)
-      nokogiri (>= 1.6)
-    rails-html-sanitizer (1.3.0)
-      loofah (~> 2.3)
-    railties (5.2.4.2)
-      actionpack (= 5.2.4.2)
-      activesupport (= 5.2.4.2)
-      method_source
-      rake (>= 0.8.7)
-      thor (>= 0.19.0, < 2.0)
-    rake (13.0.3)
-    slim (4.1.0)
-      temple (>= 0.7.6, < 0.9)
-      tilt (>= 2.0.6, < 2.1)
-    slim-rails (3.2.0)
-      actionpack (>= 3.1)
-      railties (>= 3.1)
-      slim (>= 3.0, < 5.0)
-    temple (0.8.2)
-    thor (1.1.0)
-    thread_safe (0.3.6)
-    tilt (2.0.10)
-    tzinfo (1.2.9)
-      thread_safe (~> 0.1)
-
-PLATFORMS
-  ruby
-
-DEPENDENCIES
-  slim-rails
-
-BUNDLED WITH
-   2.1.4