migration.scripts: add attachments.{channel, message}_id

- schema.sql: remove message_attachments table

    it is uneeded since we have the columns in attachments

manage/cmd/migration/scripts/10_add_attachments_table.sql

@@ -1,6 +1,9 @@
 CREATE TABLE IF NOT EXISTS attachments (
     id bigint PRIMARY KEY,
 
+    channel_id bigint REFERENCES channels (id),
+    message_id bigint REFERENCES messages (id),
+
     filename text NOT NULL,
     filesize integer,
 
@@ -10,12 +13,3 @@ CREATE TABLE IF NOT EXISTS attachments (
     height integer DEFAULT NULL,
     width integer DEFAULT NULL
 );
-
--- recreate the attachments table since
--- its been always error'ing since some migrations ago.
-CREATE TABLE IF NOT EXISTS message_attachments (
-    message_id bigint REFERENCES messages (id),
-    attachment bigint REFERENCES attachments (id),
-    PRIMARY KEY (message_id, attachment)
-);
-

schema.sql

@@ -56,6 +56,11 @@ CREATE TABLE IF NOT EXISTS instance_invites (
 CREATE TABLE IF NOT EXISTS attachments (
     id bigint PRIMARY KEY,
 
+    -- keeping channel_id and message_id
+    -- make a way "better" attachment url.
+    channel_id bigint REFERENCES channels (id),
+    message_id bigint REFERENCES messages (id),
+
     filename text NOT NULL,
     filesize integer,
 
@@ -634,12 +639,6 @@ CREATE TABLE IF NOT EXISTS messages (
     message_type int NOT NULL
 );
 
-CREATE TABLE IF NOT EXISTS message_attachments (
-    message_id bigint REFERENCES messages (id),
-    attachment bigint REFERENCES attachments (id),
-    PRIMARY KEY (message_id, attachment)
-);
-
 CREATE TABLE IF NOT EXISTS message_reactions (
     message_id bigint REFERENCES messages (id),
     user_id bigint REFERENCES users (id),