add features

source/features.rst

+Features
+========
+
+Subject management
+------------------
+
+At its core, castellum can be used to record which subjects have participated
+in which studies. This allows to keep track of all data related to a subject,
+e.g. to export or delete all of it on request.
+
+Relevant guides:
+
+-   :ref:`subject-create`
+-   :ref:`subject-delete`
+-   :ref:`study-create`
+-   :ref:`study-delete`
+
+.. TODO::
+
+    -   add subject to study
+    -   get a subject's pseudonym
+    -   maintenance
+
+Recruitment
+-----------
+
+It is possible to find potential subjects for a study from the pool of subjects
+that have been entered into castellum. They can then be contacted either
+manually or automatically via email. Subjects are only considered if they have
+given consent to recruitment and if their attributes match the filters that
+have been defined in the study.
+
+Relevant guides:
+
+-   :ref:`consent`
+-   :ref:`recruitment`
+
+.. TODO::
+
+    -   manage attribute descriptions
+    -   attribute download
+
+Appointments
+------------
+
+Castellum can be used to manage appointments for test session. It will send
+reminder mails to subjects automatically. You can also define resources such as
+rooms or machines that can not be used in more than one appointment at a time.
+
+Relevant guides:
+
+.. TODO::
+
+    -   manage study sessions
+    -   make appointments
+    -   manage resources
+    -   access calendar feeds
+    -   use external scheduler
+
+Misc
+----
+
+.. TODO::
+
+    -   custom groups
+    -   news

source/guides/consent-management.rst

+.. _consent:
+
 Consent Management
 ==================
 

source/guides/deleting.rst

+.. _subject-delete:
+
 Data Protection: Deleting a subject from Castellum
 ==================================================
 
@@ -37,6 +39,8 @@ please proceed as follows:
         -   Delete all of these study participations by clicking on **Delete** next to
             **Study details**
 
+.. _study-delete:
+
 Data Maintenance: Deleting a study from Castellum
 =================================================
 

source/guides/study-creation.rst

+.. _study-create:
+
 Study Coordination: Creating a new study
 ========================================
 

source/guides/study-recruitment.rst

+.. _recruitment:
+
 Recruitment of participants for a study
 =======================================
 

source/guides/subject-management.rst

+.. _subject-create:
+
 Subject Management: Creating a subject in Castellum
 ===================================================
 

source/index.rst

@@ -11,6 +11,7 @@ Welcome to castellum-docs's documentation!
 
    overview
    security
+   features
    roles
 
 .. toctree::