lowercase standardization

docs/API.md

@@ -120,7 +120,7 @@ User{
     ```json
     {
         "code":601,
-        "errors":["Email already taken"]
+        "errors":["email already taken"]
     }
     ```
 

server/api/user_handler.go

@@ -192,7 +192,7 @@ func doesUserExist(repo *repository.Repository, user *models.User) *HTTPError {
 		return &HTTPError{
 			Code: ErrUserValidateFields,
 			Errors: []string{
-				"Email already taken",
+				"email already taken",
 			},
 		}
 	}

server/api/user_handler_test.go

@@ -117,7 +117,7 @@ var createUserTests = []userTest{
 			"password": "hello"
 		}`,
 		expStatus: http.StatusUnprocessableEntity,
-		expBody:   `{"code":601,"errors":["Email already taken"]}`,
+		expBody:   `{"code":601,"errors":["email already taken"]}`,
 		canQuery:  true,
 	},
 }