diff --git a/CHANGELOG.md b/CHANGELOG.md
new file mode 100644
--- /dev/null
+++ b/CHANGELOG.md
@@ -0,0 +1,6 @@
+## 0.5
+
+* `JSONSchema` instances for `Data.Vector`, `Data.Map`, and `Data.HashMap`
+* Add `Map` type for json objects with arbitrary keys
+* Add `Any` type for any json value
+* Don't generate empty field names in ojbects for constructors without labeled fields
diff --git a/README.md b/README.md
new file mode 100644
--- /dev/null
+++ b/README.md
@@ -0,0 +1,3 @@
+# json-schema
+
+[![Build Status](https://travis-ci.org/silkapp/json-schema.svg?branch=master)](https://travis-ci.org/silkapp/json-schema)
diff --git a/json-schema.cabal b/json-schema.cabal
--- a/json-schema.cabal
+++ b/json-schema.cabal
@@ -1,31 +1,40 @@
-Name:                json-schema
-Version:             0.4
-Synopsis:            Types and type classes for defining JSON schemas.
-Description:         Types and type classes for defining JSON schemas.
-License:             BSD3
-License-file:        LICENSE
-Author:              Silk
-Maintainer:          code@silk.co
-Category:            Data
-Build-type:          Simple
-Cabal-version:       >=1.6
+name:                json-schema
+version:             0.5
+synopsis:            Types and type classes for defining JSON schemas.
+description:         Types and type classes for defining JSON schemas.
+license:             BSD3
+license-file:        LICENSE
+author:              Silk
+maintainer:          code@silk.co
+category:            Data
+build-type:          Simple
+cabal-version:       >=1.6
 
-Library
-  Hs-Source-Dirs:    src
-  Exposed-Modules:   Data.JSON.Schema
-                   , Data.JSON.Schema.Combinators
-                   , Data.JSON.Schema.Generic
-                   , Data.JSON.Schema.Types
-  Build-Depends:     base == 4.*
-                   , aeson >= 0.6 && < 0.8
-                   , containers >= 0.3 && < 0.6
-                   , generic-aeson == 0.1.*
-                   , generic-deriving == 1.6.*
-                   , tagged >= 0.2 && < 0.8
-                   -- No bounds, since we only use the Text type.
-                   , text
-  Ghc-Options:       -Wall
+extra-source-files:
+  CHANGELOG.md
+  LICENSE
+  README.md
 
-Source-repository head
-  Type:              Git
-  Location:          https://github.com/silkapp/json-schema.git
+source-repository head
+  type:              git
+  location:          https://github.com/silkapp/json-schema.git
+
+library
+  ghc-options:       -Wall
+  hs-source-dirs:    src
+  exposed-modules:
+    Data.JSON.Schema
+    Data.JSON.Schema.Combinators
+    Data.JSON.Schema.Generic
+    Data.JSON.Schema.Types
+  build-depends:
+      base == 4.*
+    , aeson >= 0.6 && < 0.8
+    , containers >= 0.3 && < 0.6
+    , generic-aeson == 0.1.*
+    , generic-deriving == 1.6.*
+    , tagged >= 0.2 && < 0.8
+    -- No bounds, since we only use the Text type.
+    , text
+    , unordered-containers == 0.2.*
+    , vector == 0.10.*
diff --git a/src/Data/JSON/Schema/Generic.hs b/src/Data/JSON/Schema/Generic.hs
--- a/src/Data/JSON/Schema/Generic.hs
+++ b/src/Data/JSON/Schema/Generic.hs
@@ -1,11 +1,12 @@
-{-# LANGUAGE TypeOperators
-           , TupleSections
-           , ScopedTypeVariables
-           , FlexibleContexts
-           , FlexibleInstances
-           , OverlappingInstances
-           , TypeFamilies
-           #-}
+{-# LANGUAGE
+    FlexibleContexts
+  , FlexibleInstances
+  , OverlappingInstances
+  , ScopedTypeVariables
+  , TupleSections
+  , TypeFamilies
+  , TypeOperators
+  #-}
 -- | Generic derivation of schemas. The schemas generated match the
 -- JSON generated by type 'generic-aeson' package. See that package
 -- for documentation on the format and examples of it.
@@ -76,11 +77,16 @@
 instance (Selector c, JSONSchema a) => GJSONSCHEMA (M1 S c (K1 i (Maybe a))) where
   gSchema' _ _ = field (selName (undefined :: M1 S c f p)) False . schema . fmap (fromJust . unK1 . unM1)
 
+-- TODO This instance does not correspond to the generic-aeson representation for Maybe
 instance Selector c => GJSONSCHEMA (M1 S c (K1 i (Maybe String))) where
   gSchema' _ _ _ = field (selName (undefined :: M1 S c f p)) False $ Value 0 (-1)
 
 instance (Selector c, GJSONSCHEMA f) => GJSONSCHEMA (M1 S c f) where
-  gSchema' mc enm = field (selName (undefined :: M1 S c f p)) True . gSchema' mc enm . fmap unM1
+  gSchema' mc enm = wrap . gSchema' mc enm . fmap unM1
+    where
+      wrap = case selName (undefined :: M1 S c f p) of
+        "" -> id
+        s -> field s True
 
 multipleConstructors :: (Generic a, ConNames (Rep a)) => Proxy a -> Bool
 multipleConstructors = (> 1) . length . conNames . pv
diff --git a/src/Data/JSON/Schema/Types.hs b/src/Data/JSON/Schema/Types.hs
--- a/src/Data/JSON/Schema/Types.hs
+++ b/src/Data/JSON/Schema/Types.hs
@@ -1,11 +1,19 @@
-{-# LANGUAGE FlexibleInstances, TypeSynonymInstances #-}
+{-# LANGUAGE
+    FlexibleInstances
+  , TypeSynonymInstances
+  #-}
 -- | Types for defining JSON schemas.
 module Data.JSON.Schema.Types where
 
 import Data.Maybe
 import Data.Proxy
+import Data.String
 import Data.Text (Text)
+import Data.Vector (Vector)
 import Data.Word (Word32)
+import qualified Data.HashMap.Strict as H
+import qualified Data.Map            as M
+import qualified Data.Vector         as V
 
 -- | A schema is any JSON value.
 type Schema = Value
@@ -14,6 +22,7 @@
 data Value =
     Choice [Value] -- ^ A choice of multiple values, e.g. for sum types.
   | Object [Field] -- ^ A JSON object.
+  | Map    Value   -- ^ A JSON object with arbitrary keys.
   | Array Int Int Bool Value -- ^ An array. The integers represent the
                              -- lower and upper bound of the array
                              -- size. The value -1 indicates no bound.
@@ -28,6 +37,7 @@
                     -- upper bound on the value. The value -1
                     -- indicates no bound.
   | Null
+  | Any
   deriving (Eq, Show)
 
 -- | A field in an object.
@@ -60,3 +70,12 @@
 
 instance JSONSchema a => JSONSchema [a] where
   schema = Array 0 (-1) False . schema . fmap head
+
+instance JSONSchema a => JSONSchema (Vector a) where
+  schema = Array 0 (-1) False . schema . fmap V.head
+
+instance (IsString k, JSONSchema v) => JSONSchema (M.Map k v) where
+  schema = Map . schema . fmap (head . M.elems)
+
+instance (IsString k, JSONSchema v) => JSONSchema (H.HashMap k v) where
+  schema = Map . schema . fmap (head . H.elems)