Allow to schedule resource allocations on just one day

modules/resource_management/app/models/resource_allocation.rb

@@ -160,7 +160,7 @@ class ResourceAllocation < ApplicationRecord
 
   def end_date_after_start_date
     return if start_date.blank? || end_date.blank?
-    return if end_date > start_date
+    return if end_date >= start_date
 
     errors.add :end_date, :greater_than_start_date
   end

modules/resource_management/spec/models/resource_allocation_spec.rb

@@ -400,9 +400,8 @@ RSpec.describe ResourceAllocation do
           allocation.end_date = Date.new(2026, 1, 1)
         end
 
-        it "is invalid" do
-          expect(allocation).not_to be_valid
-          expect(allocation.errors.symbols_for(:end_date)).to include(:greater_than_start_date)
+        it "is valid (single-day allocation)" do
+          expect(allocation).to be_valid
         end
       end