Remove guard-cucumber

Looks dead, last commit over two years ago, and block upgrade of cucumber

See guard/guard-cucumber#36

Gemfile

@@ -240,7 +240,6 @@ end
 group :development do
   # Automatic test runs
   gem "guard",          "2.15.0", require: false
-  gem "guard-cucumber", "2.1.2", require: false
   gem "guard-rspec",    "4.7.3", require: false
   gem "guard-rubocop",  "1.3.0", require: false
   gem "rb-fsevent",     "0.10.3", require: false

Gemfile.lock

@@ -266,10 +266,6 @@ GEM
       shellany (~> 0.0)
       thor (>= 0.18.1)
     guard-compat (1.2.1)
-    guard-cucumber (2.1.2)
-      cucumber (~> 2.0)
-      guard-compat (~> 1.0)
-      nenv (~> 0.1)
     guard-rspec (4.7.3)
       guard (~> 2.1)
       guard-compat (~> 1.1)
@@ -793,7 +789,6 @@ DEPENDENCIES
   fuubar (= 2.3.2)
   gon (= 6.2.1)
   guard (= 2.15.0)
-  guard-cucumber (= 2.1.2)
   guard-rspec (= 4.7.3)
   guard-rubocop (= 1.3.0)
   haml_lint (= 0.28.0)

Guardfile

@@ -23,17 +23,6 @@ guard :rspec, cmd: "bin/spring rspec", all_on_start: false, all_after_pass: fals
   watch(%r{^app/views/(.+)/.*\.(erb|haml)$})          {|m| "spec/requests/#{m[1]}_spec.rb" }
 end
 
-guard(:cucumber,
-      cmd:            "bin/spring cucumber",
-      all_on_start:   false,
-      all_after_pass: false) do
-  watch(/^features\/.+\.feature$/)
-  watch(%r{^features/support/.+$})          { "features" }
-  watch(%r{^features/step_definitions/(.+)_steps\.rb$}) {|m|
-    Dir[File.join("**/#{m[1]}.feature")][0] || "features"
-  }
-end
-
 guard :rubocop, all_on_start: false, keep_failed: false do
   watch(/(?:app|config|db|lib|features|spec)\/.+\.rb$/)
   watch(/(config.ru|Gemfile|Guardfile|Rakefile)$/)