Add some comment in the files manipulating the session DB

libraries/session-storage/impl/src/main/sqldelight/io/element/android/libraries/matrix/session/SessionData.sq

@@ -1,3 +1,7 @@
+------------------------------------
+--  Current version of the DB: 4  --
+------------------------------------
+
 CREATE TABLE SessionData (
     userId TEXT NOT NULL PRIMARY KEY,
     deviceId TEXT NOT NULL,
@@ -5,8 +9,11 @@ CREATE TABLE SessionData (
     refreshToken TEXT,
     homeserverUrl TEXT NOT NULL,
     slidingSyncProxy TEXT,
+    -- added in version 2
     loginTimestamp INTEGER,
+    -- added in version 3
     oidcData TEXT,
+    -- added in version 4
     isTokenValid INTEGER NOT NULL DEFAULT 1,
     loginType TEXT
 );

libraries/session-storage/impl/src/main/sqldelight/migrations/0.sqm

@@ -1,3 +1,6 @@
+-- This file is not striclty necessary, since the first
+-- version of the DB is 1, so we will never migrate from 0
+
 CREATE TABLE SessionData (
     userId TEXT NOT NULL PRIMARY KEY,
     deviceId TEXT NOT NULL,

libraries/session-storage/impl/src/main/sqldelight/migrations/1.sqm

@@ -1 +1,3 @@
+-- Migrate DB from version 1
+
 ALTER TABLE SessionData ADD COLUMN loginTimestamp INTEGER;

libraries/session-storage/impl/src/main/sqldelight/migrations/2.sqm

@@ -1 +1,3 @@
+-- Migrate DB from version 2
+
 ALTER TABLE SessionData ADD COLUMN oidcData TEXT;

libraries/session-storage/impl/src/main/sqldelight/migrations/3.sqm

@@ -1,2 +1,4 @@
+-- Migrate DB from version 3
+
 ALTER TABLE SessionData ADD COLUMN isTokenValid INTEGER NOT NULL DEFAULT 1;
 ALTER TABLE SessionData ADD COLUMN loginType TEXT;