[RAILS] Added checks for proper launch order to the example application templates

In order to prevent confusing errors when users try to run templates not
sequentially, added checks which ensure the templates are run properly
one after another.

Author: karmi

elasticsearch-rails/lib/rails/templates/02-pretty.rb

@@ -1,6 +1,9 @@
 # $ rails new searchapp --skip --skip-bundle --template https://raw.github.com/elasticsearch/elasticsearch-rails/master/elasticsearch-rails/lib/rails/templates/02-pretty.rb
 
-# (See: 01-basic.rb)
+unless File.read('README.rdoc').include? '== [1] Basic'
+  say_status  "ERROR", "You have to run the 01-basic.rb template first.", :red
+  exit(1)
+end
 
 puts
 say_status  "README", "Updating Readme...\n", :yellow

elasticsearch-rails/lib/rails/templates/03-expert.rb

@@ -1,6 +1,9 @@
 #     $ rails new searchapp --skip --skip-bundle --template https://raw.github.com/elasticsearch/elasticsearch-rails/master/elasticsearch-rails/lib/rails/templates/03-expert.rb
 
-# (See: 01-basic.rb, 02-pretty.rb)
+unless File.read('README.rdoc').include? '== [2] Pretty'
+  say_status  "ERROR", "You have to run the 01-basic.rb and 02-pretty.rb templates first.", :red
+  exit(1)
+end
 
 append_to_file 'README.rdoc', <<-README
 

elasticsearch-rails/lib/rails/templates/04-dsl.rb

@@ -1,6 +1,9 @@
 #     $ rails new searchapp --skip --skip-bundle --template https://raw.githubusercontent.com/elastic/elasticsearch-rails/master/elasticsearch-rails/lib/rails/templates/04-dsl.rb
 
-# (See: 01-basic.rb, 02-pretty.rb, 03-expert.rb)
+unless File.read('README.rdoc').include? '== [3] Expert'
+  say_status  "ERROR", "You have to run the 01-basic.rb, 02-pretty.rb and 03-expert.rb templates first.", :red
+  exit(1)
+end
 
 append_to_file 'README.rdoc', <<-README