Provide the Fish function

Signed-off-by: Clement Escoffier <clement.escoffier@gmail.com>

fish/jenv.fish

@@ -0,0 +1,18 @@
+set PATH $HOME/.jenv/shims $PATH
+command jenv rehash 2>/dev/null
+function jenv
+  set cmd $argv[1]
+  set arg ""
+  if test (count $argv) -gt 1
+    # Great... fish first array index is ... 1 !
+    set arg $argv[2..-1]
+  end
+
+  switch "$cmd"
+    case enable-plugin rehash shell shell-options
+        set script (jenv "sh-$cmd" "$arg")
+        eval $script
+    case '*'
+        command jenv $cmd $arg
+    end
+end