Fix how we access Event::Base.payload hash

In this hash, keys are strings not symbols.

src/api/app/models/event/relationship_create.rb

@@ -6,9 +6,9 @@ class RelationshipCreate < Relationship
     receiver_roles :any_role
 
     def subject
-      object = payload[:project]
-      object += "/#{payload[:package]}" if payload[:package]
-      "#{payload[:who]} added you as #{payload[:role]} on #{object}"
+      object = payload['project']
+      object += "/#{payload['package']}" if payload['package']
+      "#{payload['who']} added you as #{payload['role']} on #{object}"
     end
   end
 end

src/api/app/models/event/relationship_delete.rb

@@ -6,9 +6,9 @@ class RelationshipDelete < Relationship
     receiver_roles :any_role
 
     def subject
-      object = payload[:project]
-      object += "/#{payload[:package]}" if payload[:package]
-      "#{payload[:who]} added you as #{payload[:role]} on #{object}"
+      object = payload['project']
+      object += "/#{payload['package']}" if payload['package']
+      "#{payload['who']} added you as #{payload['role']} on #{object}"
     end
   end
 end

src/api/app/models/event/report_for_comment.rb

@@ -5,7 +5,7 @@ class ReportForComment < Report
                  :project_name, :package_name, :commenter
 
     def subject
-      "Comment by #{payload[:commenter]} reported"
+      "Comment by #{payload['commenter']} reported"
     end
   end
 end

src/api/app/models/event/report_for_package.rb

@@ -4,7 +4,7 @@ class ReportForPackage < Report
     payload_keys :package_name, :project_name
 
     def subject
-      "Package #{payload[:project_name]}/#{payload[:package_name]} reported"
+      "Package #{payload['project_name']}/#{payload['package_name']} reported"
     end
 
     def self.notification_link_path(notification)

src/api/app/models/event/report_for_project.rb

@@ -4,7 +4,7 @@ class ReportForProject < Report
     payload_keys :project_name
 
     def subject
-      "Project #{payload[:project_name]} reported"
+      "Project #{payload['project_name']} reported"
     end
 
     def self.notification_link_path(notification)

src/api/app/models/event/report_for_request.rb

@@ -4,7 +4,7 @@ class ReportForRequest < Report
     payload_keys :bs_request_number
 
     def subject
-      "Request #{payload[:bs_request_number]} reported"
+      "Request #{payload['bs_request_number']} reported"
     end
   end
 end

src/api/app/models/event/report_for_user.rb

@@ -4,7 +4,7 @@ class ReportForUser < Report
     payload_keys :user_login
 
     def subject
-      "User #{payload[:user_login]} reported"
+      "User #{payload['user_login']} reported"
     end
   end
 end