Set up mima-run executable

mima-run/Main.hs

@@ -0,0 +1,4 @@
+module Main where
+
+main :: IO ()
+main = putStrLn "In the beginning, there was nothing."

package.yaml

@@ -26,6 +26,17 @@ dependencies:
 library:
   source-dirs: src
 
+executables:
+  mima-run:
+    source-dirs: mima-run
+    main: Main.hs
+    ghc-options:
+      - -threaded
+      - -rtsopts
+      - -with-rtsopts=-N
+    dependencies:
+      - mima-tools
+
 tests:
   spec:
     source-dirs: test