Fixes refinery#1897 by defining generator_command in all generators.

core/lib/generators/refinery/engine/engine_generator.rb

@@ -33,6 +33,10 @@ def generate
 
   protected
 
+    def generator_command
+      'rails generate refinery:engine'
+    end
+
     def reject_file_with_skip_frontend?(file)
       (skip_frontend? && (file.to_s.include?('app') && file.to_s.scan(/admin|models|mailers/).empty?)) ||
         reject_file_without_skip_frontend?(file)

core/lib/generators/refinery/form/form_generator.rb

@@ -11,10 +11,6 @@ def description
       "Generates an extension which is set up for frontend form submissions like a contact page."
     end
 
-    def generator_command
-      'rails generate refinery:form'
-    end
-
     def generate
       sanity_check!
 
@@ -29,5 +25,11 @@ def generate
       finalize_extension!
     end
 
+    protected
+
+    def generator_command
+      'rails generate refinery:form'
+    end
+
   end
 end

core/lib/refinery/extension_generation.rb

@@ -208,6 +208,10 @@ def gemfile
       end
     end
 
+    def generator_command
+      raise "You must override the method 'generator_command' in your generator."
+    end
+
     def merge_locales!
       if existing_extension?
         # go through all of the temporary files and merge what we need into the current files.
@@ -304,11 +308,12 @@ def sanity_check!
         else
           "Please specify the singular name '#{singular_name.singularize}' instead of '#{plural_name}'."
         end
-        exit_with_message!(message)
+        exit_with_message! message
       end
 
       if attributes.empty? && self.behavior != :revoke
-        exit_with_message!("You must specify a name and at least one field. For help: #{generator_command}")
+        exit_with_message! "You must specify a name and at least one field." \
+                           "\nFor help, run: #{generator_command}"
       end
     end