Pushed scm nix for mdb v3

moonstreamdb-v3/scm/scm.nix

@@ -0,0 +1,29 @@
+with builtins;
+let
+    scm_repos = [
+        (getEnv "SCM_GIT")
+        (fetchGit {
+            url = "git@gitlab.com:deltaex/schematic.git";
+            rev = "deccf9c3af9d381ebcf43b4684f2a9fc12ca2df7";
+        })
+    ];
+    scm_repo = head (filter (x: x != "") scm_repos);
+    scm = (import scm_repo {
+        verbose = true;
+        repos = [
+            "."
+            (getEnv "MDP_GIT")
+            (fetchGit {
+                url = "git@github.com:moonstream-to/api.git";
+                rev = "d45333dc0ec0f2233c66472ce9346bd2827756ed";
+            })
+        ] ++ scm_repos;
+    });
+in rec {
+    schematic = scm.shell.overrideAttrs ( oldAttrs : {
+        shellHook = oldAttrs.shellHook + ''
+            [ -n "$ENV" -a "$ENV" != "dev" ]
+            source /home/moonstream/moonstream-db-v3-secrets/pg.env
+        '';
+    });
+}