diff --git a/CHANGELOG.md b/CHANGELOG.md
new file mode 100644
--- /dev/null
+++ b/CHANGELOG.md
@@ -0,0 +1,10 @@
+# Version 0.0.2
+
+* Unexported `Moto.PostgreSQL.withRegistry`. See issue #19.
+
+* Made compatible with `di-df1` version `1.2`.
+
+
+# Version 0.0.1
+
+* Initial version.
diff --git a/README.md b/README.md
new file mode 100644
--- /dev/null
+++ b/README.md
@@ -0,0 +1,5 @@
+moto-postgresql
+===============
+
+This library provides a PostgreSQL-based migrations registry for the
+`moto` migrations library.
diff --git a/Setup.hs b/Setup.hs
deleted file mode 100644
--- a/Setup.hs
+++ /dev/null
@@ -1,2 +0,0 @@
-import Distribution.Simple
-main = defaultMain
diff --git a/lib/Moto/PostgreSQL.hs b/lib/Moto/PostgreSQL.hs
--- a/lib/Moto/PostgreSQL.hs
+++ b/lib/Moto/PostgreSQL.hs
@@ -4,28 +4,37 @@
 
 module Moto.PostgreSQL
   ( registryConf
-  , withRegistry
   ) where
 
 import qualified Control.Exception.Safe as Ex
 import Control.Monad.IO.Class (MonadIO, liftIO)
 import qualified Data.ByteString as B
 import qualified Data.ByteString.Char8 as B8
-import Data.Foldable (foldlM)
+import Data.Foldable (foldlM, for_)
 import qualified Data.List as List
+import qualified Data.Text as T
+import qualified Data.Text.Encoding as T
 import qualified Database.PostgreSQL.Simple as Pg
 import qualified Database.PostgreSQL.Simple.FromRow as Pg
 import qualified Database.PostgreSQL.Simple.FromField as Pg
 import qualified Database.PostgreSQL.Simple.ToRow as Pg
 import qualified Database.PostgreSQL.Simple.ToField as Pg
 import qualified Database.PostgreSQL.Simple.Types as Pg
+import qualified Di.Df1 as Di
 import qualified Moto
 import qualified Moto.Registry as Moto
+import qualified System.Environment as IO
 
 --------------------------------------------------------------------------------
 
+-- | PostgreSQL connection URI.
+--
+-- See https://www.postgresql.org/docs/current/static/libpq-connect.html#LIBPQ-CONNSTRING
+newtype ConnectionURI = ConnectionURI B.ByteString
+  deriving (Eq, Show)
+
 -- | Command-line configuration for a 'Moto.Registry' stored in an append-only
--- table in a PostgreSQL database, as supported by 'withRegistry'.
+-- table in a PostgreSQL database.
 --
 -- The table name shall be @registry@, inside a schema named @moto@.
 registryConf :: Moto.RegistryConf
@@ -33,11 +42,7 @@
   { Moto.registryConf_help =
       "URI to the database where registry is stored. \
       \See https://www.postgresql.org/docs/current/static/libpq-connect.html#LIBPQ-CONNSTRING"
-  , Moto.registryConf_parse = \s -> do
-      case any (flip List.isPrefixOf s) ["postgres://", "postgresql://"] of
-        False -> Left "Registry URI should start with 'postgresql://' \
-                      \or 'postgres://'"
-        True -> Right (B8.pack s)
+  , Moto.registryConf_parse = Right . ConnectionURI . T.encodeUtf8 . T.pack
   , Moto.registryConf_with = withRegistry
   }
 
@@ -47,14 +52,21 @@
 -- The table name shall be @registry@, inside a schema named @moto@.
 withRegistry
   :: (MonadIO m, Ex.MonadMask m)
-  => B.ByteString
-  -- ^ PostgreSQL [connection string](https://www.postgresql.org/docs/current/static/libpq-connect.html#LIBPQ-CONNSTRING).
+  => Di.Df1
+  -> ConnectionURI
   -> (Moto.Registry -> m a)
   -> m a
-withRegistry cs k = Ex.bracket
-  (liftIO (Pg.connectPostgreSQL cs)) -- TODO don't let env vars affect this
-  (liftIO . Pg.close)
+withRegistry di0 (ConnectionURI cu) k = Ex.bracket
+  (liftIO $ do
+     checkPgEnvVars di0
+     Di.debug_ di0 "Connecting to PostgreSQL database..."
+     Pg.connectPostgreSQL cu)
+  (\conn -> liftIO $ do
+     Di.debug_ di0 "Closing connection to PostgreSQL database..."
+     Pg.close conn)
   (\conn -> k =<< liftIO (do
+     Di.debug_ di0 "Creating necessary tables, if any, \
+                   \and acquiring exclusive registry lock..."
      -- Lock to prevent multiple executions of this program to touch the table.
      -- Then get our initial state, creating our table if necessary.
      logs :: [LogV1] <- Pg.query_ conn
@@ -69,6 +81,7 @@
         \ , dir text NULL );\
         \SET client_min_messages = notice;\n\
         \SELECT act, t, mid, dir FROM moto.registry ORDER BY ord ASC;"
+     Di.debug_ di0 "Loading state from registry..."
      state0 :: Moto.State <- either Ex.throwM pure $ do
         foldlM Moto.updateState Moto.emptyState (map unLogV1 logs)
      Moto.newAppendOnlyRegistry state0 $ \log_ -> do
@@ -120,4 +133,53 @@
           Pg.Null <- Pg.field
           pure (Moto.Log_Commit t)
       s -> fail ("bad action: " ++ show (s :: String))
+
+--------------------------------------------------------------------------------
+
+checkPgEnvVars :: Di.Df1 -> IO ()
+checkPgEnvVars di0 = do
+  for_ pgEnvVars $ \(ne, ncs) -> do
+     yev <- IO.lookupEnv ne
+     for_ yev $ \ev -> do
+        let ex = Err_PgEnvVar ne ncs
+        Di.error di0 (Ex.displayException ex)
+        Ex.throwM ex
+
+data Err_PgEnvVar = Err_PgEnvVar String String
+  deriving (Show)
+
+instance Ex.Exception Err_PgEnvVar where
+  displayException (Err_PgEnvVar ne ncs) =
+    "Detected '" <> ne <> "' environment variable. We don't like this, we \
+    \could be accidentally using another PostgreSQL database configuration. \
+    \Please set '" <> ncs <> "' in the connection string instead."
+
+-- | A map from PG* environment variables to their connection string
+-- counterpart.
+pgEnvVars :: [(String, String)]
+pgEnvVars =
+  [ ("PGHOST", "host")
+  , ("PGHOSTADDR", "hostaddr")
+  , ("PGPORT", "port")
+  , ("PGDATABASE", "dbname")
+  , ("PGUSER", "user")
+  , ("PGPASSWORD", "password")
+  , ("PGPASSFILE", "passfile")
+  , ("PGSERVICE", "service")
+  , ("PGOPTIONS", "options")
+  , ("PGAPPNAME", "application_name")
+  , ("PGSSLMODE", "sslmode")
+  , ("PGREQUIRESSL", "requiressl")
+  , ("PGSSLCOMPRESSION", "sslcompression")
+  , ("PGSSLCERT", "sslcert")
+  , ("PGSSLKEY", "sslkey")
+  , ("PGSSLROOTCERT", "sslrootcert")
+  , ("PGSSLCRL", "sslcrl")
+  , ("PGREQUIREPEER", "requirepeer")
+  , ("PGKRBSRVNAME", "krbsrvname")
+  , ("PGGSSLIB", "gsslib")
+  , ("PGCONNECT_TIMEOUT", "connect_timeout")
+  , ("PGCLIENTENCODING", "client_encoding")
+  , ("PGTARGETSESSIONATTRS", "target_session_attrs")
+  ]
 
diff --git a/moto-postgresql.cabal b/moto-postgresql.cabal
--- a/moto-postgresql.cabal
+++ b/moto-postgresql.cabal
@@ -1,13 +1,16 @@
 name: moto-postgresql
-version: 0.0.1
+version: 0.0.2
 synopsis: PostgreSQL-based migrations registry for moto.
 license: Apache-2.0
 license-file: LICENSE.txt
+extra-source-files: README.md CHANGELOG.md
 author: Renzo Carbonara
 maintainer: ren@ren!zone
 category: Database
 build-type: Simple
 cabal-version: >=2.0
+homepage: https://gitlab.com/k0001/moto
+bug-reports: https://gitlab.com/k0001/moto/issues
 
 library
   hs-source-dirs: lib
@@ -17,6 +20,9 @@
   build-depends:
       base (>=4.6 && <5.0),
       bytestring,
-      postgresql-simple,
+      df1,
+      di-df1,
       moto,
-      safe-exceptions
+      postgresql-simple,
+      safe-exceptions,
+      text