Disallow reserved words for identifiers (#5)

Table and column names may not use reserved words. This does not
included SQL standard defined non-reserve words. Some of these words
are also parser keywords so they will return a different error, that's
OK, just as long as the name itself can not be used.

.github/workflows/ci.yml

@@ -17,5 +17,7 @@ jobs:
       with:
         v-version: latest
       id: v
+    - name: Verify fmt
+      run: v fmt -verify .
     - name: Run SQL tests
       run: v -stats test vsql

README.md

@@ -227,6 +227,11 @@ There are some types that are not supported yet:
 | `SMALLINT`             | f64      | Integer |
 | `VARCHAR(n)`           | string   | Alias for `CHARACTER VARYING(n)` |
 
+### Keywords
+
+Names of entities (such as tables and columns) cannot be a
+[reserved word](https://github.com/elliotchance/vsql/blob/main/vsql/keywords.v).
+
 ### SQLSTATE (Errors)
 
 The error returned from `query()` will always one of the `SQLState` struct

tests/errors.sql

@@ -1,2 +1,2 @@
 TABLE
--- error: vsql.SQLState42601: syntax error at "TABLE"
+-- error: vsql.SQLState42601: syntax error: at "TABLE"