(document): Add created ts and file format.

data/schema.sql

@@ -189,9 +189,10 @@ CREATE TABLE stamp_types (
 
 CREATE TABLE documents (
   document_id INTEGER GENERATED ALWAYS AS IDENTITY PRIMARY KEY,
-  document_data VARCHAR NOT NULL,
+  document_data TEXT NOT NULL,
   seal INTEGER NOT NULL,
-  metadata TEXT
+  metadata TEXT,
+  created_at TIMESTAMPTZ NOT NULL DEFAULT NOW()
 );
 
 CREATE TABLE document_stamps (

src/datamodels.py

@@ -103,9 +103,10 @@ class DataModel(Registry):
         ------
         CREATE TABLE documents (
           document_id INTEGER GENERATED ALWAYS AS IDENTITY PRIMARY KEY,
-          document_data VARCHAR NOT NULL,
+          document_data TEXT NOT NULL,
           seal INTEGER NOT NULL,
-          metadata TEXT
+          metadata TEXT,
+          created_at TIMESTAMPTZ NOT NULL DEFAULT NOW()
         );
         """
         _tablename_ = 'documents'
@@ -115,6 +116,7 @@ class DataModel(Registry):
         document_data = Column()
         seal = Integer()
         metadata = String()
+        created_at = Timestamp()
 
     class DocumentStamp(RowModel):
         """