Merged in feature/instruments (pull request #22)

Add subtitle to instruments

server/basicknowledge/models.py

@@ -4,7 +4,7 @@ from wagtail.core.fields import StreamField
 from wagtail.images.blocks import ImageChooserBlock
 
 from books.blocks import LinkBlock, VideoBlock, DocumentBlock, SectionTitleBlock, InfogramBlock, \
-    GeniallyBlock, InstrumentTextBlock
+    GeniallyBlock, InstrumentTextBlock, SubtitleBlock
 from core.wagtail_utils import StrictHierarchyPage
 
 
@@ -20,6 +20,7 @@ class BasicKnowledge(StrictHierarchyPage):
         ('section_title', SectionTitleBlock()),
         ('infogram_block', InfogramBlock()),
         ('genially_block', GeniallyBlock()),
+        ('subtitle', SubtitleBlock()),
     ], null=True, blank=True)
 
     LANGUAGE_COMMUNICATION = 'language_communication'