Use describe on feature tests

The `type: :feature` is automatically detected by RSpec because these
tests are inside the `spec/features` folder. Using `feature` re-adds a
`type: :feature` to these files, which will result in a conflict when we
upgrade to Rails 5.1's system tests.

Because of this change, we also need to change `background` to `before`
or else these tests will fail.

spec/features/votes_spec.rb

@@ -1,14 +1,14 @@
 require "rails_helper"
 
-feature "Votes" do
+describe "Votes" do
 
-  background do
+  before do
     @manuela = create(:user, verified_at: Time.current)
     @pablo = create(:user)
   end
 
-  feature "Debates" do
-    background { login_as(@manuela) }
+  describe "Debates" do
+    before { login_as(@manuela) }
 
     scenario "Index shows user votes on debates" do
 
@@ -59,7 +59,7 @@ feature "Votes" do
       end
     end
 
-    feature "Single debate" do
+    describe "Single debate" do
 
       scenario "Show no votes" do
         visit debate_path(create(:debate))
@@ -184,8 +184,8 @@ feature "Votes" do
     end
   end
 
-  feature "Proposals" do
-    background { login_as(@manuela) }
+  describe "Proposals" do
+    before { login_as(@manuela) }
 
     scenario "Index shows user votes on proposals" do
       proposal1 = create(:proposal)
@@ -210,8 +210,8 @@ feature "Votes" do
       end
     end
 
-    feature "Single proposal" do
-      background do
+    describe "Single proposal" do
+      before do
         @proposal = create(:proposal)
       end
 
@@ -368,8 +368,8 @@ feature "Votes" do
     end
   end
 
-  feature "Spending Proposals" do
-    background do
+  describe "Spending Proposals" do
+    before do
       Setting["feature.spending_proposals"] = true
       Setting["feature.spending_proposal_features.voting_allowed"] = true
       login_as(@manuela)
@@ -380,7 +380,7 @@ feature "Votes" do
       Setting["feature.spending_proposal_features.voting_allowed"] = nil
     end
 
-    feature "Index" do
+    describe "Index" do
       scenario "Index shows user votes on proposals" do
         spending_proposal1 = create(:spending_proposal)
         spending_proposal2 = create(:spending_proposal)
@@ -417,8 +417,8 @@ feature "Votes" do
       end
     end
 
-    feature "Single spending proposal" do
-      background do
+    describe "Single spending proposal" do
+      before do
         @proposal = create(:spending_proposal)
       end