add the installation guide on ubuntu, including binary install and source install

doc/install_gogs_from_binary_on_ubuntu.md

@@ -0,0 +1,22 @@
+sudo apt-get update
+sudo apt-get upgrade
+
+sudo apt-get install git
+sudo apt-get install golang
+sudo apt-get install mysql-server
+$mysql -u root -p
+mysql> SET GLOBAL storage_engine = 'InnoDB';
+mysql> CREATE DATABASE gogs CHARACTER SET utf8 COLLATE utf8_bin;
+mysql> GRANT ALL PRIVILEGES ON gogs.* TO 'root'@'localhost' IDENTIFIED BY 'password';
+mysql> FLUSH PRIVILEGES;
+mysql> QUIT
+
+
+mkdir gogs
+cd gogs
+curl -L http://gobuild.io/github.com/gogits/gogs/v0.2.0/linux/amd64 -o v0.2.0.zip
+unzip v0.2.0.zip
+./start.sh
+
+> The up-to-date binary could be found at
+> http://gobuild.io/download/github.com/gogits/gogs

doc/install_gogs_from_source_on_ubuntu.md

@@ -0,0 +1,48 @@
+#Install gogs under ubuntu 14.04 LTS 32bit from source code
+
+##Requirements
+### Go Programming Language: Version >= 1.2
+### git(bash): Version >= 1.6.6(both server and client) 
+### MySQL: Version >= 5.1 or PostgreSQL or NOTHING. 
+
+## Create the user which will run git
+sudo  adduser git
+su git
+
+## Install git and Mysql-server
+sudo apt-get install git
+sudo apt-get install mysql-server
+
+## Create database
+$mysql -u root -p
+mysql> SET GLOBAL storage_engine = 'InnoDB';
+mysql> CREATE DATABASE gogs CHARACTER SET utf8 COLLATE utf8_bin;
+mysql> GRANT ALL PRIVILEGES ON gogs.* TO 'root'@'localhost' IDENTIFIED BY 'pasword';
+mysql> FLUSH PRIVILEGES;
+mysql> QUIT
+
+## install go from source
+sudo apt-get install build-essential 
+sudo apt-get install mercurial
+hg clone -r release https://go.googlecode.com/hg/ /home/git/golang/
+ 
+
+echo export GOROOT=/home/git/golang >>.bashrc
+echo export GOARCH=386   >>.bashrc 
+echo export GOOS=linux  >>.bashrc 
+echo export GOBIN= /home/git/golang/bin  >>.bashrc 
+echo export GOPATH=$HOME/app/Go   >>.bashrc 
+echo  PATH=${PATH}: /$HOME/golang/bin  >>.bashrc
+cd $GOROOT/src
+./make.bash
+
+## Download and install dependencies
+$ go get -u github.com/gogits/gogs
+
+## Build main program
+$ cd $GOPATH/src/github.com/gogits/gogs
+$ go build
+$ ./start.sh
+
+## At present, you could access gogs from http://localhost:3000
+