Remove db tasks

These tasks were only necessary for the capistrano-alchemy gem, which
now can do this without Alchemy's direct help.

lib/tasks/alchemy/db.rake

@@ -1,29 +1,13 @@
 # frozen_string_literal: true
-require 'shellwords'
+
 require 'alchemy/seeder'
-require 'alchemy/tasks/helpers'
 
 namespace :alchemy do
   namespace :db do
-    include Alchemy::Tasks::Helpers
 
     desc "Seeds the database with Alchemy defaults"
     task seed: [:environment] do
       Alchemy::Seeder.seed!
     end
-
-    desc "Dumps the database to STDOUT (Pass DUMP_FILENAME to store the dump into a file)."
-    task dump: :environment do
-      dump_store = ENV['DUMP_FILENAME'] ? " > #{ENV['DUMP_FILENAME']}" : ""
-      dump_cmd = database_dump_command(database_config['adapter'])
-      system "#{dump_cmd}#{dump_store}"
-    end
-
-    desc "Imports the database from STDIN (Pass DUMP_FILENAME to read the dump from file)."
-    task import: :environment do
-      dump_store = ENV['DUMP_FILENAME'] ? "cat #{ENV['DUMP_FILENAME']}" : "echo #{Shellwords.escape(STDIN.read)}"
-      import_cmd = database_import_command(database_config['adapter'])
-      system "#{dump_store} | #{import_cmd}"
-    end
   end
 end