Import feature for following/blocking lists (addresses #62, #177, #201, #454)

app/workers/import_worker.rb

@@ -0,0 +1,54 @@
+# frozen_string_literal: true
+
+require 'csv'
+
+class ImportWorker
+  include Sidekiq::Worker
+
+  sidekiq_options retry: false
+
+  def perform(import_id)
+    import = Import.find(import_id)
+
+    case import.type
+    when 'blocking'
+      process_blocks(import)
+    when 'following'
+      process_follows(import)
+    end
+
+    import.destroy
+  end
+
+  private
+
+  def process_blocks(import)
+    from_account = import.account
+
+    CSV.foreach(import.data.path) do |row|
+      next if row.size != 1
+
+      begin
+        target_account = FollowRemoteAccountService.new.call(row[0])
+        next if target_account.nil?
+        BlockService.new.call(from_account, target_account)
+      rescue Goldfinger::Error, HTTP::Error, OpenSSL::SSL::SSLError
+        next
+      end
+    end
+  end
+
+  def process_follows(import)
+    from_account = import.account
+
+    CSV.foreach(import.data.path) do |row|
+      next if row.size != 1
+
+      begin
+        FollowService.new.call(from_account, row[0])
+      rescue Goldfinger::Error, HTTP::Error, OpenSSL::SSL::SSLError
+        next
+      end
+    end
+  end
+end