add migration version limitation note in docs (close #1108) (#1413)

docs/graphql/manual/migrations/auto-apply-migrations.rst

@@ -1,5 +1,5 @@
-Auto-apply migrations or metadata when server starts
-====================================================
+Auto-apply migrations/metadata when server starts
+=================================================
 
 .. contents:: Table of contents
   :backlinks: none
@@ -23,7 +23,7 @@ Applying migrations
 
 The ``migrations`` directory created by Hasura CLI (the one next to 
 ``config.yaml``) can be mounted at ``/hasura-migrations`` path of this docker
-container and the container's entrypoint script will apply the migrations before
+container and the container's entry point script will apply the migrations before
 starting the server. If no directory is mounted at the designated path, server
 will start ignoring migrations.
 
@@ -53,4 +53,4 @@ Applying only metadata
 
 If you're managing migrations with a different tool and want to use this image to apply only the
 metadata, mount a directory with just a ``metadata.yaml`` file and the script will
-apply the meatadata.
+apply the metadata.

docs/graphql/manual/migrations/existing-project.rst

@@ -114,6 +114,10 @@ Step 3: Initialize the migrations as per your current state
 
 - Remove ``migrations/<version>_first.down.{sql,yaml}`` migration files if you are not adding down migrations for these
 
+.. note::
+
+  Migration version cannot be "0". i.e. the files cannot be of the form ``0_<something>.up.sql``
+
 Step 4: Use the console from the CLI
 ------------------------------------
 
@@ -135,7 +139,7 @@ in the ``migrations/`` directory in your project.
 
 .. note::
 
-   Migrations are only created when using the Console through CLI.
+   Migrations are only created when using the console through CLI.
 
 Step 6: Apply the migrations to another instance of the GraphQL engine
 ----------------------------------------------------------------------

docs/graphql/manual/migrations/index.rst

@@ -42,4 +42,4 @@ Advanced
    For new project <new-project>
    For existing project <existing-project>
    With a database with an existing migration system <database-with-migrations>
-   Auto-apply migrations or metadata when server starts <auto-apply-migrations>
+   Auto-apply migrations/metadata when server starts <auto-apply-migrations>