Add Makefile and Travis CI build (#200)

* Add Makefile and Travis CI build

* Simplify the script

* Add to contributing guideline

* Include Go modules and tools.go

* Remove new line at eof

.travis.yml

@@ -0,0 +1,17 @@
+language: go
+cache:
+  directories:
+    - /home/travis/gopath/pkg/mod
+
+go:
+  - 1.12.x
+
+env:
+  global:
+    GO111MODULE=on
+
+install:
+  - make install-tools
+
+script:
+  - make travis-ci

Makefile

@@ -0,0 +1,21 @@
+# All documents to be used in spell check.
+ALL_DOC := $(shell find . -name '*.md' -type f | sort)
+
+MISSPELL=misspell -error
+MISSPELL_CORRECTION=misspell -w
+
+.PHONY: travis-ci
+travis-ci: misspell
+
+.PHONY: misspell
+misspell:
+	$(MISSPELL) $(ALL_DOC)
+
+.PHONY: misspell-correction
+misspell-correction:
+	$(MISSPELL_CORRECTION) $(ALL_DOC)
+
+.PHONY: install-tools
+install-tools:
+	GO111MODULE=on go install \
+	  github.com/client9/misspell/cmd/misspell

go.mod

@@ -0,0 +1,5 @@
+module github.com/open-telemetry/opentelemetry-specification
+
+go 1.12
+
+require github.com/client9/misspell v0.3.4

go.sum

@@ -0,0 +1,2 @@
+github.com/client9/misspell v0.3.4 h1:ta993UF76GwbvJcIo3Y68y/M3WxlpEHPWIGDkJYwzJI=
+github.com/client9/misspell v0.3.4/go.mod h1:qj6jICC3Q7zFZvVWo7KLAzC3yx5G7kyvSDkc90ppPyw=

internal/tools.go

@@ -0,0 +1,27 @@
+// Copyright 2019, OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+
+// +build tools
+
+package internal
+
+// This file follows the recommendation at
+// https://github.com/golang/go/wiki/Modules#how-can-i-track-tool-dependencies-for-a-module
+// on how to pin tooling dependencies to a go.mod file.
+// This ensures that all systems use the same version of tools in addition to regular dependencies.
+
+import (
+	_ "github.com/client9/misspell/cmd/misspell"
+)