add boolean type

DESIGN.md

@@ -130,6 +130,8 @@ set exclusion.
 A *date* is a 64 bit unsigned integer representing a TAI64. It supports the following constraints:
 before, after.
 
+A *boolean* is `true` or `false`.
+
 ### Usage
 
 A biscuit token defines some scopes for facts and rules. The *authority* scope is defined in the first

SPECIFICATIONS.md

@@ -121,6 +121,8 @@ constraints: equal, set inclusion, set exclusion.
 A *date* is a 64 bit unsigned integer representing a TAI64. It supports the
 following constraints: before, after.
 
+A *boolean* is `true` or `false`.
+
 ### Authority and ambient facts
 
 Facts in Biscuit's language have some specific context.

schema.proto

@@ -198,6 +198,7 @@ message IDV1 {
     string string = 4;
     uint64 date = 5;
     bytes bytes = 6;
+    bool bool = 7;
   }
 }