Added a helper function to remove a variable from the model

src/builder.rs

@@ -1,6 +1,7 @@
 use crate::{ffi, proto};
 use proto::constraint_proto::Constraint as CstEnum;
 use smallvec::SmallVec;
+use crate::proto::LinearArgumentProto;
 
 /// A builder for CP SAT.
 ///
@@ -98,6 +99,27 @@ impl CpModelBuilder {
         self.new_int_var_with_name(domain, "")
     }
 
+    /// Removes the [IntVar] whose name matches the given name from the model.
+    ///
+    /// # Example
+    ///
+    /// ```
+    /// # use cp_sat::builder::{CpModelBuilder, IntVar};
+    /// let mut model = CpModelBuilder::default();
+    /// let x = model.new_int_var_with_name([(0, 1)], "some cool name");
+    /// assert!(!model.proto().variables.is_empty());
+    /// let name = model.remove_int_var("some cool name");
+    /// assert!(model.proto().variables.is_empty());
+    pub fn remove_int_var(&mut self, name: &str) {
+        let position = self
+          .proto
+          .variables
+          .iter()
+          .position(|variable| variable.name == name)
+          .unwrap();
+        self.proto.variables.remove(position);
+    }
+
     /// Creates a new integer variable with a name, and returns the
     /// [IntVar] indentifier.
     ///