Fix foreign key constraint in entries_data (#665)

store/sqlite/migrations/012-fix-entries_data-foreign-key.sql

@@ -0,0 +1,21 @@
+-- In migration 003, we didn't update entries_data to point to the new entries
+-- table, so we have to fix it here. For some reason, the sqlite3 database
+-- driver we were using at the time (mattn/go-sqlite3) didn't notice the
+-- violation of the FOREIGN KEY constraint.
+CREATE TABLE new_entries_data (
+    id TEXT,
+    chunk_index INTEGER,
+    chunk BLOB,
+    FOREIGN KEY (id) REFERENCES entries (id)
+);
+
+INSERT INTO new_entries_data
+SELECT
+    id,
+    chunk_index,
+    chunk
+FROM entries_data;
+
+DROP TABLE entries_data;
+
+ALTER TABLE new_entries_data RENAME TO entries_data;