Fix README and gitignore

Author: oin

.gitignore

@@ -13,3 +13,4 @@
 .externalNativeBuild
 .cxx
 local.properties
+/app/release

README.md

@@ -134,7 +134,7 @@ The characters in bold are the ones that are marked on the labels of the keys.
 | **`x`** | **`7`**, `×`, `χ` |
 | **`c`** | **`8`**, `ç` `©`, `¢`, `⊂`, `⊄`, `⊃`, `⊅` |
 | **`v`** | **`9`**, `∀`, `√` |
-| **` ` (space bar)** | `	` (tab), |
+| **` ` (space bar)** | `	` (tab), `⇥` |
 | **`b`** | **`.`**, `…`, `ß`, `∫`, `♭` |
 | **`n`** | **`,`**, `ñ`, `¬`, `∩` |
 | **`m`** | **`?`**, `$`, `€`, `£`, `¿` |