diff --git a/Model.hs b/Model.hs
index 353bafb..f6820d4 100644
--- a/Model.hs
+++ b/Model.hs
@@ -3,6 +3,8 @@ module Model where
 import ClassyPrelude.Yesod
 import Database.Persist.Quasi
 
+import PersistSHA1
+
 -- You can define all of your database entities in the entities file.
 -- You can find more information on persistent and how to declare entities
 -- at:
diff --git a/PersistSHA1.hs b/PersistSHA1.hs
new file mode 100644
index 0000000..a25e766
--- /dev/null
+++ b/PersistSHA1.hs
@@ -0,0 +1,23 @@
+module PersistSHA1 where
+
+import ClassyPrelude.Yesod
+import Database.Persist.Sql
+
+import qualified Data.ByteString as B
+import qualified Data.ByteString.Char8 as BC
+import Numeric (showHex)
+
+data SHA1 = SHA1 ByteString
+            deriving Show
+
+toHex :: ByteString -> ByteString
+toHex = BC.pack . concat . (map (flip showHex "")) . B.unpack
+
+instance PersistField SHA1 where
+  toPersistValue (SHA1 t) = PersistDbSpecific t
+
+  fromPersistValue (PersistDbSpecific t) = Right $ SHA1 $ B.concat ["E'\\x", toHex(t), "'"]
+  fromPersistValue _ = Left "SHA1 values must be converted from PersistDbSpecific"
+
+instance PersistFieldSql SHA1 where
+  sqlType _ = SqlOther "BYTEA"
diff --git a/config/models b/config/models
index cd7d6ca..d6a4947 100644
--- a/config/models
+++ b/config/models
@@ -8,5 +8,27 @@ Email
     user UserId Maybe
     verkey Text Maybe
     UniqueEmail email
-
- -- By default this file is used in Model.hs (which is imported by Foundation.hs)
+Repo
+    url Text
+    branch Text
+    currentCommit SHA1
+    owner UserId
+    ready Bool default=False
+    stamp UTCTime default=now()
+    UniqueUrlBranch url branch
+    deriving Show
+Challenge
+    publicRepo RepoId
+    privateRepo RepoId
+    name Text
+    UniqueName name
+    title Text
+    description Text
+    stamp UTCTime default=now()
+Test
+    challenge ChallengeId
+    checksum SHA1
+    commit SHA1
+    active Bool default=True
+    UniqueChallengeChecksum challenge checksum
+-- By default this file is used in Model.hs (which is imported by Foundation.hs)
diff --git a/gonito.cabal b/gonito.cabal
index 5145464..36e3c8a 100644
--- a/gonito.cabal
+++ b/gonito.cabal
@@ -18,6 +18,7 @@ library
                      Import
                      Import.NoFoundation
                      Model
+                     PersistSHA1
                      Settings
                      Settings.StaticFiles
                      SharedTypes