[WIP] See if we can avoid gemfiles

.github/workflows/ci.yml

@@ -5,7 +5,7 @@ on: [push, pull_request]
 jobs:
   build:
     runs-on: ubuntu-latest
-    name: Ruby ${{ matrix.ruby }} | Rails ${{ matrix.rails }} | Gemfile ${{ matrix.gemfile }}
+    name: Ruby ${{ matrix.ruby }} | Rails ${{ matrix.rails }}
     continue-on-error: ${{ matrix.rails == 'edge' }}
     services:
       redis:
@@ -17,7 +17,6 @@ jobs:
         ruby: ["2.6", "2.7", "3.0", "3.1", "3.2", "3.3"]
         rails:
           ["~> 5.2.0", "~> 6.0.0", "~> 6.1.0", "~> 7.0.0", "~> 7.1.0", "edge"]
-        gemfile: [rails_gems]
         exclude:
           - ruby: "2.6"
             rails: "~> 7.0.0"
@@ -55,9 +54,7 @@ jobs:
         include:
           - ruby: head
             rails: "edge"
-            gemfile: rails_gems
     env:
-      BUNDLE_GEMFILE: gemfiles/${{ matrix.gemfile }}.gemfile
       RAILS_GEMS_REQUIREMENTS: ${{ matrix.rails }}
     steps:
       - name: Check out code

Gemfile

@@ -11,12 +11,14 @@ gemspec
 gem "sidekiq"
 gem "resque"
 
-if defined?(@rails_gems_requirements) && @rails_gems_requirements
+if (rails_gems_requirements = ENV["RAILS_GEMS_REQUIREMENTS"])
+  rails_gems_requirements = { github: "rails/rails", branch: "main" } if rails_gems_requirements == "edge"
+
   # We avoid the `gem "..."` syntax here so Dependabot doesn't try to update these gems.
   [
     "activejob",
     "activerecord",
-  ].each { |name| gem name, @rails_gems_requirements }
+  ].each { |name| gem name, rails_gem_requirements }
 else
   # gem "activejob" # Set in gemspec
   gem "activerecord"