Added shelter and things needed for it (incomplete)

systems/world.py

@@ -1,7 +1,26 @@
 from data.cat import Cat
+import systems.ui as ui
+import re
+
+
+def check_cat_name(name):
+    name = name.strip()
+    if not name:
+        return "Please choose a name:"
+    if len(name) > 4 or len(name) < 20:
+        return "Please choose a name greater than 4 charecters and less than 20:"
+    if re.search(r"[^a-zA-Z \-']", name):
+        return "Please only use letters, spaces, hyphens and apostrophes:"
+    return "Ok"
 
 
 def shelter():
     # TODO: make
-    name = input("Name your cat: ")
+    name = ui.text("Welcome to the shelter! Please choose a name for your cat:")
+    while True:
+        check_result = check_cat_name(name)
+        if check_result != "Ok":
+            name = ui.text(check_result)
+        else:
+            break
     return Cat(name)