Added Gemfile.lock to .gitignore.

It's not necessary to track exact details of the gems used in this
project as they are used for build purposes only.

.gitignore

@@ -0,0 +1 @@
+Gemfile.lock

Gemfile.lock

@@ -1,28 +0,0 @@
-GEM
-  remote: https://rubygems.org/
-  specs:
-    equatable (0.5.0)
-    git-cop (1.7.1)
-      pastel (~> 0.7)
-      refinements (~> 4.2)
-      runcom (~> 1.3)
-      thor (~> 0.20)
-    pastel (0.7.2)
-      equatable (~> 0.5.0)
-      tty-color (~> 0.4.0)
-    rake (12.3.0)
-    refinements (4.3.0)
-    runcom (1.4.0)
-      refinements (~> 4.2)
-    thor (0.20.0)
-    tty-color (0.4.2)
-
-PLATFORMS
-  ruby
-
-DEPENDENCIES
-  git-cop (~> 1.7)
-  rake (~> 12.0)
-
-BUNDLED WITH
-   1.16.0