Add backup and ocr backend documentation chapters.

docs/topics/backups.rst

@@ -0,0 +1,16 @@
+=======
+Backups
+=======
+
+To backup your install of Mayan EDMS just copy the actual document files and
+the database content. If you are using the default storage backend, the
+document files should be found in ``mayan/media/document_storage/``.
+
+To dump the content of your database manager refer to the documentation chapter
+regarding database data "dumping".
+
+Example:
+
+ - Postgresl: http://www.postgresql.org/docs/current/static/backup.html
+ - MySQL: https://dev.mysql.com/doc/refman/5.7/en/mysqldump.html
+ - SQLite: Just copy the file ``mayan/media/db.sqlite3``

docs/topics/index.rst

@@ -15,9 +15,11 @@ Introductions to all the key parts of Mayan EDMS you'll need to know:
    checkouts
    versioning
    signatures
+   ocr_backend
    indexes
    smart_links
    tags
    mailing
    file_storage
+   backups
    screenshots

docs/topics/ocr_backend.rst

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+===========
+OCR backend
+===========
+
+Mayan EDMS ships an OCR backend that uses the FLOSS engine Tesseract, but it can
+use other engines. To support other engines a wrapper that subclasess the
+``OCRBackendBase`` class defined in mayan/apps/ocr/classes. This subclass should
+expose the ``execute`` method. For an example of how the Tesseract backend
+is implemented take a look at the file ``mayan/apps/ocr/backends/tesseract.py``
+
+Once you create you own backend, in your local.py settings add the option
+OCR_BACKEND and point it to your new OCR backend class path.
+
+The default value of OCR_BACKEND is ``"ocr.backends.tesseract.Tesseract"``
+